@article {7549, title = {Mapping and Geomorphic Characterization of the Vast Cold-Water Coral Mounds of the Blake Plateau}, volume = {4(1)}, year = {2024}, month = {12 January 2024}, pages = {17-47}, publisher = {MDPI}, abstract = {

A coordinated multi-year ocean exploration campaign on the Blake Plateau offshore of the south-23 eastern U.S. has mapped what appears to be the most expansive cold-water coral (CWC) mound 24 province thus far discovered. Nearly continuous CWC mound features span an area up to 500 km 25 long and 110 km wide, with a core area of high density mounds up to 254 km long by 42 km wide. 26 This study synthesized bathymetric data from 31 multibeam sonar mapping surveys and generated 27 a standardized geomorphic classification of the region in order to delineate and quantify CWC 28 mound habitats and compare mound morphologies among subregions of the coral province. Based 29 on the multibeam bathymetry, a total of 83,908 individual peak features were delineated, providing 30 the first estimate of the overall number of potential CWC mounds mapped in the region to date. 31 Five geomorphic landform classes were mapped and quantified: peaks (411 km2), valleys (3,598 32 km2), ridges (3,642 km2), slopes (23,082 km2), and flats (102,848 km2). The complex geomorphology 33 of eight subregions was described qualitatively with geomorphic \“fingerprints\” (spatial patterns) 34 and quantitatively by measurements of mound density and vertical relief. This study demonstrated 35 the value of applying an objective automated terrain segmentation and classification approach to 36 geomorphic characterization of a highly complex CWC mound province. Manual delineation of 37 these features in a consistent repeatable way with a comparable level of detail would not have been 38 possible.

}, keywords = {automated, bathymetry, Blake Plateau, cold-water corals, Desmophyllum, geomorphology, Lophelia, mapping, multibeam sonar, Ocean exploration, reef}, doi = {https://doi.org/10.3390/geomatics4010002}, url = {https://www.mdpi.com/2673-7418/4/1/2}, author = {Derek Sowers and Larry A Mayer and Giuseppe Masetti and Erik Cordes and Ryan Gasbarro and Elizabeth Lobecker and Kasey Cantwell and Samuel Candio and Shannon Hoy and Mashkoor A Malik and Michael White and Matt Dornback} } @article {7554, title = {BathyGlobe GapFiller: A Planning Tool to Help Fill the Gaps in World Bathymetry}, volume = {29(2)}, year = {2023}, month = {November 30}, pages = {16-27}, publisher = {International Hydrographic Organization}, abstract = {

To efficiently map the oceans in support of the SeaBed 2030 project and other mapping programs, newly collected mapping lines should ideally not duplicate existing data but slightly overlap prior mapping coverage. BathyGlobe GapFiller is a software tool designed to support planning for transit and area mapping. At its core is an algorithm that adjusts transit lines so that they overlap existing lines by a specified amount. Two novel methods for accomplishing this are presented. The better solution uses a custom overlap detecting filter. While it is more computationally intensive than the alternative, it performs better and is robust. Other capabilities of the BathyGlobe GapFiller are described, including swath width estimation based on system specifications and/or past performance, automatic transit planning, polygon filling, and the production of detailed statistics representing planned survey coverage, overlap and time to complete the survey.

}, keywords = {bathymetry, gap filler, mutibeam echo sounders, ocean mapping, seabed 2030, survey planning, transit planning}, doi = {https://ihr.iho.int/articles/bathyglobe-gapfiller-a-planning-tool-to-help-fill-the-gaps-in-world-bathymetry/}, author = {Ware, Colin and Larry A Mayer and Paul Johnson} } @article {7568, title = {The GEBCO_2023 Grid - A Continuous Terrain Model of the Global Oceans and Land}, year = {2023}, month = {April 18}, publisher = {NERC EDS British Oceanographic Data Centre NOC}, abstract = {

The GEBCO_2023 Grid is a global continuous terrain model for ocean and land with a spatial resolution of 15 arc seconds. In regions outside of the Arctic Ocean area, the grid uses as a base Version 2.5.5 of the SRTM15_plus data set (Tozer, B. et al, 2019). This data set is a fusion of land topography with measured and estimated seafloor topography. Included on top of this base grid are gridded bathymetric data sets developed by the four Regional Centers of The Nippon Foundation-GEBCO Seabed 2030 Project. The GEBCO_2023 Grid represents all data within the 2023 compilation. The compilation of the GEBCO_2023 Grid was carried out at the Seabed 2030 Global Center, hosted at the National Oceanography Centre, UK, with the aim of producing a seamless global terrain model. Outside of Polar regions, the Regional Centers provide their data sets as sparse grids i.e. only grid cells that contain data are populated. These data sets were included on to the base using a \&$\#$39;remove-restore\&$\#$39; blending procedure. This is a two-stage process of computing the difference between the new data and the base grid and then gridding the difference and adding the difference back to the existing base grid. The aim is to achieve a smooth transition between the new and base data sets with the minimum of perturbation of the existing base data set. The data sets supplied in the form of complete grids (primarily areas north of 60N and south of 50S) were included using feather blending techniques from GlobalMapper software. The GEBCO_2023 Grid has been developed through the Nippon Foundation-GEBCO Seabed 2030 Project. This is a collaborative project between the Nippon Foundation of Japan and the General Bathymetric Chart of the Oceans (GEBCO). It aims to bring together all available bathymetric data to produce the definitive map of the world ocean floor by 2030 and make it available to all. Funded by the Nippon Foundation, the four Seabed 2030 Regional Centers include the Southern Ocean - hosted at the Alfred Wegener Institute, Germany; South and West Pacific Ocean - hosted at the National Institute of Water and Atmospheric Research, New Zealand; Atlantic and Indian Oceans - hosted at the Lamont-Doherty Earth Observatory, Columbia University, USA; Arctic and North Pacific Oceans - hosted at Stockholm University, Sweden and the Center for Coastal and Ocean Mapping at the University of New Hampshire, USA.

}, keywords = {elevation, Oceans}, doi = {doi:10.5285/f98b053b-0cbc-6c23-e053-6c86abc0af7b}, url = {https://www.gebco.net/data_and_products/gridded_bathymetry_data/gebco_2023/}, author = {Pauline Weatherall and Michael Bogonko and Caroline Bringensparr and Sheila C{\'a}ceres Ferreras and Sara Cardigos and Boris Dorschel and Hayley Drennon and Simon Dreutter and Vicki L Ferrini and Laura Hehemann and Martin Jakobsson and Paul Johnson and Marcus Karlsson and Juliet Kinney and Kevin Mackay and Sarah M Maher and Tinah V Martin and Larry A Mayer and Jamie McMichael-Phillips and Rezwan Mohammad and Frank O Nitsche and Jaya Roperez and Silvia Salas-Romero and David T Sandwell and Yvonne Schulze Tenberge and Patrick Schwarzbach and Helen Snaith and Sacha Viquerat and GEBCO Bathymetric Compilation Group 2023 and Fynn Warnke} } @article {7551, title = {Groundtruther: A QGIS Plug-in for Seafloor Characterization, Environmental Modelling and Software}, volume = {171}, year = {2023}, month = {October 25}, abstract = {

This work focuses on developing a software system for concurrently analyzing co-located multibeam echo sounder (MBES) datasets and seafloor imagery, fulfilling the need for a unified seafloor data exploration and analysis platform. The system comprises a graphical user interface where image browsing and geospatial data are linked and several toolboxes for extracting backscatter distribution, its angular response, and bathymetric derivatives to ultimately build detailed quantitative reports. The overall objective is to provide an efficient means of understanding the relationships between morphology, backscatter, and the observed biota and, thus, understanding the relationship between the physical and ecological elements of the seafloor. In addition, Groundtruther provides new ways to interpret remotely sensed information derived from MBES and aid the development of spatial distribution models. Furthermore, it could lead to the enrichment of ground-truth databases used to develop formal geophysical models that link acoustic backscatter observations to intrinsic properties of the seafloor.

}, keywords = {GIS, Ground truth, multibeam, Remote Sensing, Seafloor images}, doi = {https://doi.org/10.1016/j.envsoft.2023.105861}, url = {https://www.sciencedirect.com/science/article/pii/S1364815223002475}, author = {Massimo Di Stefano and G. Gonzalez Mirelis and Larry A Mayer} } @article {7467, title = {Mapping and Geomorphic Characterization of the Vast Cold-Water Coral Mounds of the Blake Plateau}, year = {2023}, month = {May 29-June 2}, address = {Edinburgh, Scotland, UK}, abstract = {

The full extent of the largest cold-water coral (CWC) mound province thus far discovered has been recently revealed through multibeam sonar surveys completed during a multi-year exploration campaign on the Blake Plateau offshore of the southeastern U.S. CWC mounds in this region form distinct bumps or pinnacles (composed of slope, ridge, and peak features) readily observable in multibeam bathymetry data and were mapped in depth ranges spanning approximately 350-900 m.

Bathymetric data from 31 multibeam sonar mapping surveys were synthesized and used to generate a standardized geomorphic classification of the region in order to delineate and quantify CWC mound habitats. Seafloor terrain features were classified using the Bathymetry- and Reflectivity-based Estimator for Seafloor Segmentation (BRESS) method developed by Masetti et al. (2018) into five geomorphic landform classes (peaks, valleys, ridges, slopes, and flats) to support the enumeration of coral mound features and to quantify the area of each landform class. The \“peak\” landform class was utilized to identify and count the number of individual apparent CWC mounds.

The complex geomorphology of eight subregions representing distinct spatial patterns of CWC mound formation was described qualitatively with geomorphic \“fingerprints\” and quantitatively by measurements of mound density and vertical relief. Ground-truth for the bathymetric analysis was provided by direct substrate observations from 23 submersible dive videos that revealed coral rubble to be the dominant substrate component within the peak, ridge, and slope landforms explored, thereby validating the interpretation of these bathymetric features as CWC mounds.

The methods used in this study provide a pragmatic standardized approach for identifying, characterizing, and quantifying CWC mound-forming habitats and could be applied to other CWC provinces to enable more direct comparisons among geographically diverse settings.

}, author = {Derek Sowers and Larry A Mayer and Giuseppe Masetti and Erik Cordes and Ryan Gasbarro and Elizabeth Lobecker and Kasey Cantwell and Shannon Hoy and Michael White and Samuel Candio and Mashkoor A Malik and Matt Dornback} } @article {7541, title = {Mapping Northern Greenland Waters}, volume = {4}, year = {2023}, month = {November 3}, abstract = {

An understanding of the interplay between glaciers and the ocean is needed to improve sea-level rise projections. Seafloor mapping is critical in this pursuit, particularly where the ice sheets of Greenland and Antarctica meet the ocean. Northern Greenland\’s marine realm remains one of Earth\’s least explored areas, with completely uncharted fjords. In 2019, one of these fjords was mapped by the Swedish icebreaker Oden, with the next unmapped fjord to the east the target for 2024.

}, url = {https://www.hydro-international.com/content/article/mapping-northern-greenland-waters}, author = {Martin Jakobsson and Larry A Mayer} } @article {7550, title = {Mapping Northern Greenland Waters: A Blank Spot on Nautical Charts in Ice-Infested Waters}, volume = {27,3}, year = {2023}, month = {November 3}, pages = {17-21}, url = {https://www.hydro-international.com/content/article/mapping-northern-greenland-waters}, author = {Martin Jakobsson and Larry A Mayer} } @article {7448, title = {Uncrewed Surface Systems Facilitating a New Era of Global Ocean Exploration}, volume = {29(1)}, year = {2023}, month = {May 1}, publisher = {International Hydrographic Office (IHO)}, abstract = {

There is growing recognition that key to addressing critical issues like climate change, global sea level rise and the long-term sustainability of humankind is a more complete understanding of our oceans and processes within them that account for the distribution of global heat, CO and provide sustenance to so many. Yet, despite years of effort, less than 25\% of the global ocean seafloor has been mapped and less than 5\% of the ocean volume explored, likely due to the cost and inefficiency of traditional ocean mapping and exploration techniques using large, very expensive, crewed research vessels. Recent advances in the development of uncrewed surface vessels offer the possibility to reduce costs and increase efficiency of ocean mapping and exploration. Such efficiencies can be gained by using small mother ship-deployed uncrewed vessels acting as relatively inexpensive mapping and sampling force multipliers or the use of small uncrewed vessels launched to from a mother ship to monitor and control autonomous underwater vehicles, allowing multiple operations simultaneously and \“verified, directed sampling\”, all while freeing the mother ship for independent operations. We are also seeing the development of larger uncrewed vessels launched from shore with long-endurance and range, capable of carrying a full suite of deep ocean mapping and exploration tools. All of these systems and approaches offer great hope but it is very early in our understanding of their full capabilities, costs and limitations and we must be careful not to overpromise, leading to disappointments and early abandonment of a potentially innovative approach, while at the same time maintaining the patience required to continue the research, investment and innovation that will hopefully bring us to a new world of efficient and effective ocean mapping and exploration that will allow us to meet our goal of complete coverage of the ocean.

}, keywords = {Ocean exploration, ocean mapping, Seafloor exploration, Seafloor Mapping, Uncrewed surface vehicles}, url = {https://ihr.iho.int/articles/uncrewed-surface-systems-facilitating-a-new-era-of-global-ocean-exploration/}, author = {Larry A Mayer} } @article {7368, title = {The GEBCO 2022 Grid - A Continuous Terrain Model of the Global Oceans and Land}, year = {2022}, month = {June 22}, publisher = { NERC EDS British Oceanographic Data Centre NOC}, abstract = {

The GEBCO_2022 Grid is a global continuous terrain model for ocean and land with a spatial resolution of 15 arc seconds. In regions outside of the Arctic Ocean area, the grid uses as a base Version 2.4 of the SRTM15_plus data set (Tozer, B. et al, 2019). This data set is a fusion of land topography with measured and estimated seafloor topography. Included on top of this base grid are gridded bathymetric data sets developed by the four Regional Centers of The Nippon Foundation-GEBCO Seabed 2030 Project. The GEBCO_2022 Grid represents all data within the 2022 compilation. The compilation of the GEBCO_2022 Grid was carried out at the Seabed 2030 Global Center, hosted at the National Oceanography Centre, UK, with the aim of producing a seamless global terrain model. Outside of Polar regions, the Regional Centers provide their data sets as sparse grids i.e. only grid cells that contain data are populated. These data sets were included on to the base using a remove-restore blending procedure. This is a two-stage process of computing the difference between the new data and the base grid and then gridding the difference and adding the difference back to the existing base grid. The aim is to achieve a smooth transition between the new and base data sets with the minimum of perturbation of the existing base data set. The data sets supplied in the form of complete grids (primarily areas north of 60N and south of 50S) were included using feather blending techniques from GlobalMapper software. The GEBCO_2022 Grid has been developed through the Nippon Foundation-GEBCO Seabed 2030 Project. This is a collaborative project between the Nippon Foundation of Japan and the General Bathymetric Chart of the Oceans (GEBCO). It aims to bring together all available bathymetric data to produce the definitive map of the world ocean floor by 2030 and make it available to all. Funded by the Nippon Foundation, the four Seabed 2030 Regional Centers include the Southern Ocean - hosted at the Alfred Wegener Institute, Germany; South and West Pacific Ocean - hosted at the National Institute of Water and Atmospheric Research, New Zealand; Atlantic and Indian Oceans - hosted at the Lamont-Doherty Earth Observatory, Columbia University, USA; Arctic and North Pacific Oceans - hosted at Stockholm University, Sweden and the Center for Coastal and Ocean Mapping at the University of New Hampshire, USA.

}, keywords = {bathymetric grid, ocean map, terrain model}, url = {https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/e0f0bb80-ab44-2739-e053-6c86abc0289c/}, author = {Pauline Weatherall and Caroline Bringensparr and Castro, C.F. and Dorschel, B. and Drennon, H. and Vicki L Ferrini and Harper, H.A. and Laura Hehemann and Martin Jakobsson and Paul Johnson and Juliet Kinney and Mackay, K. and Maher, S.M. and Martin, T.V. and Larry A Mayer and McMichael-Phillips, J. and Mohammad, R. and Nitsche, F.O. and Jaya Roperez and David T Sandwell and Helen Snaith and Tozer, B. and Sacha Viquerat and Fynn Warnke and Yu, Y.} } @article {7318, title = {A Global Assessment of the Mixed Layer in Coastal Sediments and Implications for Carbon Storage}, volume = {13, 4903}, year = {2022}, month = {August 20}, abstract = {

The sediment-water interface in the coastal ocean is a highly dynamic zone controlling biogeochemical fluxes of greenhouse gases, nutrients, and metals. Processes in the sediment mixed layer (SML) control the transfer and reactivity of both particulate and dissolved matter in coastal interfaces. Here we map the global distribution of the coastal SML based on excess 210Pb (210Pbex) profiles and then use a neural network model to upscale these observations. We show that highly dynamic regions such as large estuaries have thicker SMLs than most oceanic sediments. Organic carbon preservation and SMLs are inversely related as mixing stimulates oxidation in sediments which enhances organic matter decomposition. Sites with SML thickness \>60\ cm usually have lower organic carbon accumulation rates (\<50\ g\ C m\−2 yr\−1) and total organic carbon/specific surface area ratios (\<0.4\ mg\ m\−2). Our global scale observations reveal that reworking can accelerate organic matter degradation and reduce carbon storage in coastal sediments.

}, doi = {https://doi.org/10.1038/s41467-022-32650-0}, url = {https://doi.org/10.1038/s41467-022-32650-0}, author = {Sasha Song and Isaac R. Santos and Huaming Yu and Faming Wang and William C. Burnett and Thomas S. Bianchi and Junyu Dong and Ergang Lian and Bin Zhao and Larry A Mayer and Qingzhen Yao and Zhigang Yu and Bochao Xu} } @article {7270, title = {The International Bathymetric Chart of the Southern Ocean Version 2}, volume = {9(1)}, year = {2022}, month = {June 7}, publisher = {Springer Nature}, abstract = {

The Southern Ocean surrounding Antarctica is a region that is key to a range of climatic and oceanographic processes with worldwide effects, and is characterised by high biological productivity and biodiversity. Since 2013, the International Bathymetric Chart of the Southern Ocean (IBCSO) has represented the most comprehensive compilation of bathymetry for the Southern Ocean south of 60\°S. Recently, the IBCSO Project has combined its efforts with the Nippon Foundation \– GEBCO Seabed 2030 Project supporting the goal of mapping the world\’s oceans by 2030. New datasets initiated a second version of IBCSO (IBCSO v2). This version extends to 50\°S (covering approximately 2.4 times the area of seafloor of the previous version) including the gateways of the Antarctic Circumpolar Current and the Antarctic circumpolar frontal systems. Due to increased (multibeam) data coverage, IBCSO v2 significantly improves the overall representation of the Southern Ocean seafloor and resolves many submarine landforms in more detail. This makes IBCSO v2 the most authoritative seafloor map of the area south of 50\°S.

}, doi = {10.1038/s41597-022-01366-7}, author = {Martin Jakobsson and Larry A Mayer and al et} } @article {7298, title = {The International Bathymetric Chart of the Southern Ocean Version 2}, volume = {9, 275}, year = {2022}, month = {June 7}, abstract = {

The Southern Ocean surrounding Antarctica is a region that is key to a range of climatic and oceanographic processes with worldwide effects, and is characterised by high biological productivity and biodiversity. Since 2013, the International Bathymetric Chart of the Southern Ocean (IBCSO) has represented the most comprehensive compilation of bathymetry for the Southern Ocean south of 60\°S. Recently, the IBCSO Project has combined its efforts with the Nippon Foundation \– GEBCO Seabed 2030 Project supporting the goal of mapping the world\’s oceans by 2030. New datasets initiated a second version of IBCSO (IBCSO v2). This version extends to 50\°S (covering approximately 2.4 times the area of seafloor of the previous version) including the gateways of the Antarctic Circumpolar Current and the Antarctic circumpolar frontal systems. Due to increased (multibeam) data coverage, IBCSO v2 significantly improves the overall representation of the Southern Ocean seafloor and resolves many submarine landforms in more detail. This makes IBCSO v2 the most authoritative seafloor map of the area south of 50\°S.

}, doi = {https://doi.org/10.1038/s41597-022-01366-7}, author = {Dorschel, B. and Laura Hehemann and Sacha Viquerat and Fynn Warnke and Simon Dreutter and Yvonne Schulze Tenberge and Accettella, D. and Lu An and Barrios, Felipe R and Evgenia Bazhenova and Jenny Black and Fernando Bohoyo and Craig Davey and Laura De Santis and Jennifer Jencks and Hogan, Kelly and Martin Jakobsson and Larry A Mayer and Ivan Ryzhov and al. et} } @article {7374, title = {Polar Region Bathymetry: Critical Knowledge for the Prediction of Global Sea Level Rise}, year = {2022}, month = {January 17}, abstract = {

The ocean and the marine parts of the cryosphere interact directly with, and are affected by, the seafloor and its primary properties of depth (bathymetry) and shape (morphology) in many ways. Bottom currents are largely constrained by undersea terrain with consequences for both regional and global heat transport. Deep ocean mixing is controlled by seafloor roughness, and the bathymetry directly influences where marine outlet glaciers are susceptible to the inflow relatively warm subsurface waters - an issue of great importance for ice-sheet discharge, i.e., the loss of mass from calving and undersea melting. Mass loss from glaciers and the Greenland and Antarctic ice sheets, is among the primary drivers of global sea-level rise, together now contributing more to sea-level rise than the thermal expansion of the ocean. Recent research suggests that the upper bounds of predicted sea-level rise by the year 2100 under the scenarios presented in IPCC\’s Special Report on the Ocean and Cryosphere in a Changing Climate (SROCCC) likely are conservative because of the many unknowns regarding ice dynamics. In this paper we highlight the poorly mapped seafloor in the Polar regions as a critical knowledge gap that needs to be filled to move marine cryosphere science forward and produce improved understanding of the factors impacting ice-discharge and, with that, improved predictions of, among other things, global sea-level. We analyze the bathymetric data coverage in the Arctic Ocean specifically and use the results to discuss challenges that must be overcome to map the most remotely located areas in the Polar regions in general.

}, doi = {https://doi.org/10.3389/fmars.2021.788724}, author = {Martin Jakobsson and Larry A Mayer} } @article {7216, title = {Standardized Geomorphic Characterization of the Extensive Cold-Water Coral Mound Province of the Blake Plateau, USA}, year = {2022}, month = {Feb 24 - Mar 4}, abstract = {

A strategically-planned multi-year exploration campaign on the Blake Plateau offshore of the southeastern U.S. has mapped what appears to be the most expansive cold-water coral (CWC) mound province thus far discovered. Bathymetric data from twenty multibeam sonar mapping surveys were synthesized and used to generate a standardized geomorphic classification of the region in order to delineate and quantify CWC mound habitats. CWC mounds in this region form distinct bumps or pinnacles (composed of slope, ridge, and peak features) readily observable in multibeam bathymetry data and were mapped in depth ranges spanning approximately 350-900 m. Seafloor terrain features were classified using the Bathymetry- and Reflectivity-based Estimator for Seafloor Segmentation (BRESS) method developed by Masetti et al. (2018) into five geomorphic landform classes (peaks, valleys, ridges, slopes, and flats) to support the enumeration of coral mound features and to quantify the area of each landform class. The \“peak\” landform class was utilized to identify and count the number of individual apparent CWC mounds. The complex geomorphology of eight subregions representing distinct spatial patterns of CWC mound formation was described qualitatively with geomorphic \“fingerprints\” and quantitatively by measurements of mound density and vertical relief. Ground-truth for the bathymetric analysis was provided by direct substrate observations from 23 submersible dive videos that revealed coral rubble to be the dominant substrate component within the peak, ridge, and slope landforms explored, thereby validating the interpretation of these bathymetric features as CWC mounds. The methods used in this study provide a pragmatic standardized approach for identifying, characterizing, and quantifying CWC mound-forming habitats and could be applied to other CWC provinces to enable more direct comparisons among geographically diverse settings.

}, keywords = {Geomorphic Characterization}, url = {https://osm2022.secure-platform.com/a/gallery/rounds/3/details/6986}, author = {Derek Sowers and Larry A Mayer and Giuseppe Masetti and Erik Cordes and Ryan Gasbarro and Elizabeth Lobecker and Kasey Cantwell and Shannon Hoy and Michael White and Sam Candio and Mashkoor A Malik and Matt Dornback} } @article {7219, title = {Amplified Climate Sensitivity of Northern Greenland Fjords through Sea-Ice Damming}, volume = {2(70)}, year = {2021}, month = {April 12}, abstract = {

Record-high air temperatures were observed over Greenland in the summer of 2019 and melting of the northern Greenland Ice Sheet was particularly extensive. Here we show, through direct measurements, that near surface ocean temperatures in Sherard Osborn Fjord, northern Greenland, reached 4\ \°C in August 2019, while in the neighboring Petermann Fjord, they never exceeded 0\ \°C. We show that this disparity in temperature between the two fjords occurred because thick multi-year sea ice at the entrance of Sherard Osborn Fjord trapped the surface waters inside the fjord, which led to the formation of a warm and fresh surface layer. These results suggest that the presence of multi-year sea ice increases the sensitivity of Greenland fjords abutting the Arctic Ocean to climate warming, with potential consequences for the long-term stability of the northern sector of the Greenland Ice Sheet.

}, doi = {https://doi.org/10.1038/s43247-021-00140-8}, author = {Christian Stranne and Johan Nilsson and Adam Ulfsbo and Matt O{\textquoteright}Regan and Helen K. Coxall and Lorenz Merie and Julia Muchowski and Larry A Mayer and Volker Br{\"u}chert and Jonas Fredriksson and Brett Thornton and Julek Chawarski and Gabriel West and Elizabeth Weidner and Martin Jakobsson} } @article {7014, title = {A Deep Scattering Layer Under the North Pole Pack Ice}, volume = {194}, year = {2021}, month = {June}, abstract = {

The 3.3 million km\² marine ecosystem around the North Pole, defined as the Central Arctic Ocean (CAO), is a blind spot on the map of the world\’s fish stocks. The CAO essentially comprises the permanently ice-covered deep basins and ridges outside the continental shelves, and is only accessible by ice-breakers. Traditional trawling for assessing fish stocks is impossible under the thick pack ice, and coherent hydroacoustic surveys are unachievable due to ice-breaking noise. Consequently, nothing is known about the existence of any pelagic fish stocks in the CAO, although juveniles of Boreogadus saida richly occur at the surface associated with the sea ice and ice-associated Arctogadus glacialis has been reported as well. We here present a first indication of a possible mesopelagic fish stock in the CAO. We had the opportunity to analyse a geophysical hydroacoustic data set with 13 time windows of usable acoustic data over a transect from 84.4 oN in the Nansen Basin, across the North Pole (90.0 oN), to 82.4 oN in the Canada Basin. We discovered a deep scattering layer (DSL), suggesting the presence of zooplankton and fish, at 300-600 m of depth in the Atlantic water layer of the CAO. Maximum possible fish abundance and biomass was very low; values of ca. 2,000 individuals km$^{-}$\² and ca. 50 kg km$^{-}$\² were calculated for the DSL in the North-Pole area according to a model assuming that all acoustic backscatter represents 15-cm long B. saida and/or A. glacialis. The true abundance and biomass of fish is even lower than this, but cannot be quantified from this dataset due to backscatter originating from pneumatophores of physonect siphonophores that are known to occur in the area. Further studies on the DSL of the CAO should include sampling and identification of the backscattering organisms. From our study we can conclude that if the DSL of the CAO contains fish, their biomass is currently too low for any sustainable fishery.

}, keywords = {acoustics, Arctogadus, Atlantic water layer, Boreogadus, Central Arctic Ocean (CAO), Echosounder, Siphonophore}, doi = {https://doi.org/10.1016/j.pocean.2021.102560}, author = {Snoejis-Leijonmalm, Pauline and Harald Gj{\o}s{\ae}ter and Randi B. Ingvaldsen and Tor Knutsen and Rolf Korneliussen and Egil Ona and Hein Rune Skjoldal and Christian Stranne and Larry A Mayer and Martin Jakobsson and Katarina G{\r a}rdfeldt} } @article {7170, title = {Environmental and Geomorphological Effects on the Distribution of Deep-Sea Canyon and Seamount Communities in the Northwest Atlantic}, volume = {8:691668.}, year = {2021}, month = {September 20}, abstract = {

Deep sea canyons and seamounts are topographically complex features that are considered to be biological hotspots. Anthropogenic pressures related to climate change and human activities are placing the species that inhabit these features at risk. Though studies have examined species composition on seamounts and canyons, few have compared communities between them, and even fewer studies have examined how species\’ abundances correlate with environmental conditions or geomorphology. Consequently, this study compares species composition, community structure, and environmental variables between Northwest Atlantic continental margin canyons and seamounts along the New England Seamount Chain. Geoforms were also related to the occurrence of phyla and biodiversity. Overall, there was a significant difference in species composition between canyons and seamounts with sponges, corals, sea urchins and seastars contributing heavily to observed differences. Environmental conditions of temperature and salinity and the seafloor property slope contributed significantly to communities observed on seamounts, while substrate, depth and salinity contributed significantly to canyon communities. Abundances were significantly higher in canyons, but taxonomic richness, evenness, and diversity were all greater on seamounts. In an era where climate change and human activity have the potential to alter environmental parameters in the deep sea, it is important to examine factors that influence the spatial distribution of deep-sea benthic communities.

}, keywords = {climate change, communities, corals, deep sea canyons, North Atlantic, seamounts, sponges}, doi = {10.3389/fmars.2021.691668}, url = {https://www.frontiersin.org/articles/10.3389/fmars.2021.691668/full}, author = {Kristen Mello and Derek Sowers and Mashkoor A Malik and Les Watling and Larry A Mayer and Jennifer A. Dijkstra} } @article {6957, title = {Fine-scale Mapping of Deep-Sea Habitat-Forming Species Densities Reveals Taxonomic Specific Environmental Drivers}, volume = {30}, year = {2021}, month = {May 2021}, pages = {1286-1298}, publisher = {Wiley}, abstract = {

Aim
Environmental variables are strongly tied to species occurrence and population growth, but approaches to predicting the location of deep-sea species or their ability to withstand a changing environment stem primarily from presence data. We coupled environmental data with observed densities of deep-sea habitat-forming corals and sponges to determine the environmental variables and geomorphology that contributed best to their occurrence.

Location
Northwest Atlantic.

Time period
2013 and 2014.

Major taxa studied
Deep-sea coral and sponge communities.

Methods
Multivariate and univariate analyses were used to determine significant environmental contributors to densities of genera and families of corals and sponges. We then assessed the relationship of densities of genera and families of corals and sponges with environmental variables found to be significant contributors to their occurrence and to geomorphology.

Results
Sponge and coral genera and families were influenced by different environment variables. Temperature, salinity and dissolved oxygen contributed to the occurrence of sponges, whereas seafloor properties of slope and substrate contributed to the occurrence of corals. Although individuals of corals and sponges were observed across a range of a contributing environmental variable, high densities were observed only in very narrow ranges.

Main conclusions
Geomorphic setting is an effective approach for discerning the associations of coral with seabed features. High densities of coral and sponge genera and families restricted to narrow environmental ranges might be at greater risk of local extinction. Differences in the occurrence of coral and sponge genera and families with environmental conditions suggest that they will differentially respond to predicted environmental changes. As conditions in the deep sea change with ongoing changes in climate, population expansion might be limited owing to suboptimal conditions, and established populations might persist but might have fewer individuals or species, which might lead to a loss in biodiversity.

}, keywords = {Biodiversity, climate change, coral, deep-sea canyons, geomorphology, global warming, Northwestern Atlantic, seamounts, sponge}, doi = {https://doi.org/10.1111/geb.13285}, author = {Jennifer A. Dijkstra and Kristen Mello and Derek Sowers and Mashkoor A Malik and Les Watling and Larry A Mayer} } @article {7021, title = {The Holocene Dynamics of Ryder Glacier and Ice Tongue in North Greenland}, volume = {15(8)}, year = {2021}, month = {August 24}, pages = {4073-4097}, publisher = {European Geosciences Union}, abstract = {

The northern sector of the Greenland ice sheet is considered to be particularly susceptible to ice mass loss arising from increased glacier discharge in the coming decades. However, the past extent and dynamics of outlet glaciers in this region, and hence their vulnerability to climate change, are poorly documented. In the summer of 2019, the Swedish icebreaker Oden entered the previously unchartered waters of Sherard Osborn Fjord, where Ryder Glacier drains approximately 2 \% of Greenland\&$\#$39;s ice sheet into the Lincoln Sea. Here we reconstruct the Holocene dynamics of Ryder Glacier and its ice tongue by combining radiocarbon dating with sedimentary facies analyses along a 45 km transect of marine sediment cores collected between the modern ice tongue margin and the mouth of the fjord. The results illustrate that Ryder Glacier retreated from a grounded position at the fjord mouth during the Early Holocene (\>10.7 \± 0.4 cal ka BP) and receded more than 120 km to the end of Sherard Osborn Fjord by the Middle Holocene (6.3 \± 0.3 cal ka BP), likely becoming completely land-based. A re-advance of Ryder Glacier occurred in the Late Holocene, becoming marine-based around 3.9 \± 0.4 cal ka BP. An ice tongue, similar in extent to its current position was established in the Late Holocene (between 3.6 \± 0.4 and 2.9 \± 0.4 cal ka BP) and extended to its maximum historical position near the fjord mouth around 0.9 \± 0.3 cal ka BP. Laminated, clast-poor sediments were deposited during the entire retreat and regrowth phases, suggesting the persistence of an ice tongue that only collapsed when the glacier retreated behind a prominent topographic high at the landward end of the fjord. Sherard Osborn Fjord narrows inland, is constrained by steep-sided cliffs, contains a number of bathymetric pinning points that also shield the modern ice tongue and grounding zone from warm Atlantic waters, and has a shallowing inland sub-ice topography. These features are conducive to glacier stability and can explain the persistence of Ryder\’s ice tongue while the glacier remained marine-based. However, the physiography of the fjord did not halt the dramatic retreat of Ryder Glacier under the relatively mild changes in climate forcing during the Holocene. Presently, Ryder Glacier is grounded more than 40 km seaward of its inferred position during the Middle Holocene, highlighting the potential for substantial retreat in response to ongoing climate change.

}, doi = {https://doi.org/10.5194/tc-15-4073-2021}, author = {Matt O{\textquoteright}Regan and Thomas M. Cronin and Brendan Reilly and Aage Kristian Olsen Alstrup and Laura Gemery and Anna Golub and Larry A Mayer and Morlighem, M. and Moros, Matthias and Ole Lajord Munk and Johan Nilsson and Pearce, Christof and Detlef, Henrieka and Christian Stranne and Vermassen, Flor and Gabriel West and Martin Jakobsson} } @inbook {7096, title = {The Quest to Completely Map the World{\textquoteright}s Oceans in Support of Understanding Marine Biodiversity and the Regulatory Barriers We Have Created}, booktitle = {Marine Biodiversity of Areas Beyond National Jurisdiction / Center for Ocean Law and Policy }, volume = {24}, year = {2021}, month = {February 18}, pages = {149-156}, publisher = {Brill Publishers}, organization = {Brill Publishers}, chapter = {8}, address = {Leiden, The Netherlands}, author = {Larry A Mayer and Ashley Roach}, editor = {Nordquist, M. and Ron{\'a}n Long} } @proceedings {7082, title = {Remote Estimations of Seafloor Gas Flux Using Broadband Acoustics}, year = {2021}, month = {June 21-24}, address = {Virtual}, abstract = {

Free gas bubbles escape from the seafloor worldwide and transport greenhouse gases, such as methane and carbon dioxide, into the ocean and potentially the atmosphere. These greenhouse gas emissions influence climate, contribute to upper ocean acidification, and are vital to the development of chemosynthetic biological communities. While direct observation and sampling by remotely operated vehicles (ROVs) or cable-operated camera systems help to generate quantitative estimates of gas flux, the spatial footprint and cost of such measurements prohibits rapid, large-scale, continuous gas flux estimation. Remote sensing of gas bubbles via acoustic systems offers the opportunity for surveying over much larger spatial scales at greatly reduced cost; however, without direct information about bubble parameters (e.g. size, number, composition) quantitative flux measurements cannot be made with acoustic systems alone. Consequently, quantitative gas flux estimates are rare and gas seeps remain a poorly constrained contributor to the global carbon cycle. Here, we describe an acoustic method for the remote quantification of seafloor gas flux that was developed and applied to a hydrothermal seep system in the Bay of Plenty, New Zealand. This method utilizes a calibrated broadband split-beam echo sounder to discriminate individual bubbles using high vertical range resolution and remotely estimate the bubble size distribution (BSD) of seeps. Additionally, split-beam phase differentiation provides phase-angle data, used to compensate for beam-pattern effects and deliver calibrated target strength measurements for individual seeps. Together with gas composition, individual seep BSD and target strength measurements provide a path, through acoustic inversion, for remote quantification of seafloor gas flux. Following this approach, the carbon dioxide release from a seep system in the Bay of Plenty was estimated to be 146 kg/day (standard deviations of 31.5 kg/day) from a seafloor area of approximately 0.25 km2.

}, author = {Elizabeth Weidner}, editor = {Thomas C Weber and Yoann Ladroit and Geoffroy Lamarche and Larry A Mayer} } @article {7077, title = {Spatial Analysis of Beaked Whale Foraging During Two 12 kHz Multibeam Echosounder Surveys}, volume = {8:654184}, year = {2021}, month = {August 25}, abstract = {

To add to the growing information about the effect of multibeam echosounder (MBES) operation on marine mammals, a study was conducted to assess the spatial foraging effort of Cuvier\’s beaked whales during two MBES surveys conducted in January of 2017 and 2019 off of San Clemente Island, California. The MBES surveys took place on the Southern California Antisubmarine Warfare Range (SOAR), which contains an array of 89 hydrophones covering an area of approximately 1800 km2 over which foraging beaked whales were detected. A spatial autocorrelation analysis of foraging effort was conducted using the Moran\’s I (global) and the Getis-Ord Gi\∗ (local) statistics, to understand the animals\’ spatial use of the entire SOAR, as well as smaller areas, respectively, within the SOAR Before, During, and After the two MBES surveys. In both years, the global Moran\’s I statistic suggested significant spatial clustering of foraging events on the SOAR during all analysis periods (Before, During, and After). In addition, a Kruskal-Wallis (comparison) test of both years revealed that the number of foraging events across analysis periods were similar within a given year. In 2017, the local Getis-Ord Gi\∗ analysis identified hot spots of foraging activity in the same general area of the SOAR during all analysis periods. This local result, in combination with the global and comparison results of 2017, suggest there was no obvious period-related change detected in foraging effort associated with the 2017 MBES survey at the resolution measurable with the hydrophone array. In 2019, the foraging hot spot area shifted from the southernmost corner of the SOAR Before, to the center During, and was split between the two locations After the MBES survey. Due to the pattern of period-related spatial change identified in 2019, and the lack of change detected in 2017, it was unclear whether the change detected in 2019 was a result of MBES activity or some other environmental factor. Nonetheless, the results strongly suggest that the level of detected foraging during either MBES survey did not change, and most of the foraging effort remained in the historically well-utilized foraging locations of Cuvier\’s beaked whales on the SOAR.

}, keywords = {BACI, beaked whale behavior, GLC approach, multibeam echosounder, spatial autocorrelation}, doi = {https://doi.org/10.3389/fmars.2021.654184}, author = {Hilary Kates Varghese and Kim Lowell and Jennifer Miksis-Olds and DiMarzio, N. and Moretti, D. and Larry A Mayer} } @inbook {6972, title = {Application of the Coastal and Marine Ecological Classification Standard to Gosnold Seamount, North Atlantic Ocean}, booktitle = {Seafloor Geomorphology as Benthic Habitat}, year = {2020}, month = {November 8}, pages = { 903-916}, publisher = {Elsevier}, organization = {Elsevier}, edition = {2nd }, chapter = {56}, abstract = {

This case study applied the Coastal and Marine Ecological Classification Standard (CMECS) to initial characterization of a deep-sea seamount by combining observations from a remotely operated vehicle (ROV) and information derived from multibeam sonar bathymetry and backscatter. Spatial segmentation of the multibeam bathymetry was done using algorithms based on defining bathymorphons resulting in six classes: flats, slopes, ridges, valleys, shoulders, and footslopes. These classes were modified to delineate CMECS \“Level 1\” geoform units for Gosnold Seamount. Further segmentation of landforms was completed using textural analysis of the sonar backscatter mosaic of the seamount to identify segments of the same landform type with similar reflectivity texture. All of the ROV dive video of the seafloor was analyzed manually to create a spreadsheet of 933 georeferenced annotations of organisms and associated substrate types. The dominant sediment type over each 50 m segment of the ROV track was also classified using substrate unit terminology from CMECS into four classes: bedrock (10\% of ROV track), fine unconsolidated sediments on bedrock (84\%), coral rubble (1\%), and sand (5\%). Eleven genera of corals, two classes of sponges, and four classes of echinoderms were observed along the track, with glass sponges dominating the annotation and abundance counts. Nominal regression revealed that depth, temperature, and sediment type were significant predictors of individual coral along the ROV track (P\<.001, P\<.001, P\<.001, respectively). In contrast, slope, sediment type and dissolved oxygen were significant predictors of sponge distribution along the track. In summary the application of CMECS to Gosnold Seamount provided a useful systematic framework for structuring geoform, substrate, and biotic classification of benthic habitat. Using this standard, in combination with the semiautomated seafloor segmentation approach utilized, can provide a consistent and reproducible habitat classification approach for large regions and facilitate comparison of habitats among features.

}, doi = {https://doi.org/10.1016/B978-0-12-814960-7.00056-7}, author = {Derek Sowers and Jennifer A. Dijkstra and Kristen Mello and Giuseppe Masetti and Mashkoor A Malik and Larry A Mayer}, editor = {Peter Harris and Elaine Baker} } @article {6749, title = {Applications of the Gulf of Maine Operational Forecast System to Enhance Spatio-Temporal Oceanographic Awareness for Ocean Mapping}, volume = {6:804}, year = {2020}, month = {January 2020}, publisher = {Frontiers Media}, abstract = {

Despite or perhaps because of recent technological advances in seafloor mapping systems, the resulting products and the overall operational efficiency of surveys are often affected by poor awareness of the oceanographic environment in which the surveys are conducted. Increasingly reliable ocean nowcast and forecast model predictions of key environmental variables \– from local to global scales \– are publicly available, but they are often not used by ocean mappers. With the intention of rectifying this situation, this work evaluates some possible ocean mapping applications for commonly available oceanographic predictions by focusing on one of the available regional models: NOAA\’s Gulf of Maine Operational Forecast System. The study explores two main use cases: the use of predicted oceanographic variability in the water column to enhance and extend (or even substitute) the data collected on-site by sound speed profilers during survey data acquisition; and, the uncertainty estimation of oceanographic variability as a meaningful input to estimate the optimal time between sound speed casts. After having described the techniques adopted for each use case and their implementation as an extension of publicly-available ocean mapping tools, this work provides evidence that the adoption of these techniques has the potential to improve efficiency in survey operations as well as the quality of the resulting ocean mapping products.

}, keywords = {forecast models, ocean mapping, oceanographic variability, sound speed}, doi = {https://dx.doi.org/10.3389/fmars.2019.00804}, author = {Giuseppe Masetti and Michael Smith and Larry A Mayer and John G Kelley} } @article {6868, title = {Basalts from the Chukchi Borderland: 40Ar/39Ar Ages and Geochemistry of Submarine Intraplate Lavas Dredged from the Western Arctic Ocean}, volume = {125}, year = {2020}, month = {May 11}, publisher = {American Geophysical Union}, abstract = {

Submarine volcanism in the western Arctic Ocean, known as Amerasia Basin, is attributed to a mantle plume based on geophysics and meager geochemical evidence. Basaltic samples dredged from Chukchi Borderland within the basin have produced minimum 40Ar/39Ar ages for eruption at ca. 118-112 Ma, ca. 105-100 Ma and ca. 90-70 Ma, which we use to constrain tectonic models for basin opening. Major-oxide and trace-element concentrations, and Sr, Nd, and Hf isotopic ratios of the lavas show that the ca. 118-112 Ma samples from Northwind Ridge are tholeiites (low-Ti tholeiite I) with low degrees of rare-earth-element (REE) fractionation, high overall HREE and Mg$\#$, which suggests magma derivation from a garnet-free source followed by minor crystal fractionation. Strontium, Nd and Hf isotope systematics for these lavas, and ratios of highly incompatible trace elements, point toward a lithospheric source. Eruptions at ca. 105-100 Ma and ca. 90-70 Ma, both at Healy Spur, produced two types of lavas: low-Ti tholeiite II \– which are generally older than high-Ti tholeiite \– both common in continental flood basalt (CFB) provinces, and both with trace-element abundance patterns typifying a garnet-free source, and significant crystal fractionation for the high-Ti tholeiite. The isotope characteristics for both groups are common features of asthenospheric sources. Composition-time relationships for the lavas suggest inception of melting in the sub-continental lithospheric mantle (SCLM) \– probably due to introduction of a heat source by a plume \– followed later (at ca. 105-100 Ma and ca. 90-70 Ma) by asthenospheric melting possibly triggered by plume rise.

}, doi = {https://doi.org/10.1029/2019JB017604}, author = {Mukasa, S B and Andronikov, A and Brumley, K and Larry A Mayer and Andrew A. Armstrong} } @inbook {6968, title = {Climate Change and the Legal Effects of Sea Level Rise: An Introduction to the Science}, booktitle = {New Knowledge and Changing Circumstances in the Law of the Sea}, year = {2020}, pages = {343-357}, publisher = {Brill Nijhoff Press}, organization = {Brill Nijhoff Press}, chapter = {17}, abstract = {

Since the negotiation of the United Nations Convention on the Law of the Sea, there have been many changes in our understanding of earth processes. One area of science that was not addressed in either the Convention or the Scientific and Technical Guidelines of the Commission on the Limits of the Continental Shelf is climate change and its potential impact on sea level. Recent studies have provided overwhelming and irrefutable scientific evidence that, despite a decrease in solar insolation, the average global temperature of the Earth has risen approximately 0.9\° C over the last 136 years, with most of this increase occurring over the past 35 years. This increase in temperature is the result of an increase in atmospheric CO2 that can be demonstrated (chemically) to be associated, for the most part, with the burning of fossil fuels. The increase in temperature has resulted in the thermal expansion of sea water and the melting of temperate glaciers and the Greenland and Antarctic ice sheets, driving a rise of sea level of more than 30 cm over the past 100 years. Predictions of future rise in sea level range from another 30 cm to almost a metre over the next 80 years, depending on the levels of CO2 in the atmosphere and the uncertainty of the modeling. Beyond 2100, sea level can rise even more, with predictions as much as 3 m by 2300 if there is no reduction in the rate of input of anthropogenic CO2 into the atmosphere. Along with the direct impact that sea level rise would have on residents of coastal regions, such dramatic changes in sea level will also have an impact on the area of maritime zones, boundaries with neighboring States, and, in the most dramatic cases, the inundation of islands that may lead to the partial or total disappearance of a coastal State. Changes in sea level will likely invoke the concurrent movement of the outer limits of the territorial sea, contiguous zone, and the exclusive economic zone, all of whose limits are measured from the coastal State\’s baselines. Even more intriguing is the impact of such changes in baselines on the limits of the continental shelf which are also defined relative to the baselines, but, as stated in article 76(8) of the Convention, if the limits of the continental shelf are established based on the recommendations of the Commission on the Limits of the Continental Shelf, they shall be \“final and binding.\” These and many other intriguing questions about the impact of rising sea level on maritime zones will present challenges to legal scholars in the years to come.

}, doi = {https://doi.org/10.1163/9789004437753_019}, author = {Larry A Mayer}, editor = {Tomas Heidar} } @article {6723, title = {The Effect of Two 12 kHz Multibeam Mapping Surveys on the Foraging Behavior of Cuvier{\textquoteright}s Beaked Whales Off of Southern California}, volume = {147(6)}, year = {2020}, month = {June 11}, pages = {3849-3858}, publisher = {Acoustical Society of America}, abstract = {

The impact of multibeam echosounder (MBES) operation on marine mammals has been less studied compared to military sonars. To contribute to the growing body of MBES knowledge, echolocation clicks of foraging Cuvier\’s beaked whales were detected on the Southern California Antisubmarine Warfare Range (SOAR) hydrophones during two MBES surveys, and associated into foraging events called group vocal periods (GVPs). Four GVP characteristics were analyzed Before, During, and After 12 kHz MBES surveys at SOAR in 2017 and 2019 to assess differences in foraging behavior with respect to the mapping activity. The number of GVP per hour increased During and After MBES surveys compared with Before. There were no other differences between non-MBES periods and During MBES for the three other characteristics: the number of clicks per GVP, GVP duration, and click rate. These results indicate that there was not a consistent change in foraging behavior during the MBES surveys that would suggest a clear response. The animals did not leave the range nor stop foraging during MBES activity.\ These results are in stark contrast to those of analogous studies assessing the effect of Naval mid-frequency active sonar on beaked whale foraging, where beaked whales stopped echolocating and left the area.

}, doi = {https://doi.org/10.1121/10.0001385}, author = {Hilary Kates Varghese and Jennifer Miksis-Olds and Nancy DiMarzio and Kim Lowell and Ernst Linder and Larry A Mayer and David Moretti} } @proceedings {6747, title = {The e-Learning Python for Ocean Mapping project - Empowering the Next Generation of Ocean Mappers with Effective Programming Skills}, year = {2020}, month = {February 24-27}, address = {Quebec City, Quebec, Canada}, abstract = {

The next generation of ocean mappers will need to master programming skills to face the increasingly higher expectations for timely ping-to-public data workflows. As such, the e-learning Python for Ocean Mapping (ePOM) project was established to support new ocean mapping students and professionals in reaching a minimum level of programming skills. These skills are then expanded with further powerful capabilities by leveraging the open-source Python scientific stack and the NOAA Office of Coast Survey\&$\#$39;s Pydro distribution.

}, keywords = {e-learning, juyter notebooks, programming skills, python}, doi = {https://dx.doi.org/10.13140/RG.2.2.33921.40806}, url = {https://www.conferium.com/OLM/Prg_Present.lasso?showevent=202}, author = {Giuseppe Masetti and Semme J Dijkstra and Rochelle Wigley and Greenaway, Samuel F and Damian Manda and Andrew A. Armstrong and Larry A Mayer} } @inbook {6971, title = {Geomorphology and Microhabitats of Large, Isolated, Immobile Bedforms in the Great South Channel, Northwest Atlantic Ocean}, booktitle = {Seafloor Geomorphology as Benthic Habitat}, year = {2020}, month = {November 5}, pages = {503-518}, edition = {2nd }, chapter = {29}, abstract = {

The Great South Channel (GSC) is a bathymetric feature between the Nantucket Shoals and Georges Bank that connects the southern boundary of the Gulf of Maine with the northwest Atlantic Ocean. The mid-channel is characterized by the presence of sporadic, large, and isolated bedforms on a generally sediment-starved seafloor. Exhibiting distinctive east\–west oriented straight crests, these immobile bedforms are poorly understood. In an area of active sediment transport, we have found that these bedforms have not migrated since 1998. As a result of their immobility they have ecological significance at the microhabitat scale. They increase seafloor stability on their lee side, by shielding the seafloor from erosive bottom current, thus providing a refuge for species that otherwise would not occur. Moreover, for an large straight, isolated (LSI) bedform of approximatively 16 m in height, the area shielded from erosive currents extends up to 90 m downcurrent from the bedforms.

By combining a quantitative geomorphometric characterization of high-resolution bathymetry and the concurrent analysis of coregistered seafloor images, we describe these features in detail. The fauna in the area surrounding the bedforms is found to be organized in a consistent, microscale patchiness and it is illustrated in a bedform schematic. On the whole, the immobile LSI bedforms serve as collectors of sand, which builds up on the north-facing (stoss) side forming ripples on the lower parts of the slope. Here is where the highest concentration of winter flounder can be found. On the south-facing (lee) side, the seabed is sheltered from flowing sand and the exposed, coarse gravel lag deposit is richly colonized by sessile fauna. Furthermore, the sediment in this area is very heterogeneous. Toward the center, the sediment is characterized by the presence of cobble and pebble in a matrix of gravel, as well as absence of sand. Moving away from this core area toward either side, bigger fragments can be found up to boulder size, which are exhumed by the current. In this part some sand can overcome the barrier created by the bedform and a thin layer of finer sediment is found atop and between the boulders. Besides the sessile fauna, monkfish and other mobile fauna can be found.

}, doi = {https://doi.org/10.1016/B978-0-12-814960-7.00029-4}, author = {Massimo Di Stefano and Larry A Mayer}, editor = {Peter Harris and Elaine Baker} } @article {6742, title = {Glacial Sedimentation, Fluxes and Erosion Rates Associated with Ice Retreat in Petermann Fjord and Nares Strait, North-West Greenland}, volume = {14}, year = {2020}, month = {January 28}, pages = {261-286}, publisher = {Copernicus Publications}, abstract = {

Petermann Fjord is a deep (\>1000\ m) fjord that incises the coastline of north-west Greenland and was carved by an expanded Petermann Glacier, one of the six largest outlet glaciers draining the modern Greenland Ice Sheet (GrIS). Between 5 and 70\ m of unconsolidated glacigenic material infills in the fjord and adjacent Nares Strait, deposited as the Petermann and Nares Strait ice streams retreated through the area after the Last Glacial Maximum. We have investigated the deglacial deposits using seismic stratigraphic techniques and have correlated our results with high-resolution bathymetric data and core lithofacies. We identify six seismo-acoustic facies in more than 3500 line kilometres of sub-bottom and seismic-reflection profiles throughout the fjord, Hall Basin and Kennedy Channel. Seismo-acoustic facies relate to bedrock or till surfaces (Facies I), subglacial deposition (Facies II), deposition from meltwater plumes and icebergs in quiescent glacimarine conditions (Facies III, IV), deposition at grounded ice margins during stillstands in retreat (grounding-zone wedges; Facies V) and the redeposition of material downslope (Facies IV). These sediment units represent the total volume of glacial sediment delivered to the mapped marine environment during retreat. We calculate a glacial sediment flux for the former Petermann ice stream as 1080\–1420\ m3\ a\−1 per metre of ice stream width and an average deglacial erosion rate for the basin of 0.29\–0.34\ mm\ a\−1. Our deglacial erosion rates are consistent with results from Antarctic Peninsula fjord systems but are several times lower than values for other modern GrIS catchments. This difference is attributed to fact that large volumes of surface water do not access the bed in the Petermann system, and we conclude that glacial erosion is limited to areas overridden by streaming ice in this large outlet glacier setting. Erosion rates are also presented for two phases of ice retreat and confirm that there is significant variation in rates over a glacial\–deglacial transition. Our new glacial sediment fluxes and erosion rates show that the Petermann ice stream was approximately as efficient as the palaeo-Jakobshavn Isbr\æ at eroding, transporting and delivering sediment to its margin during early deglaciation.

}, doi = {doi.org/10.5194/tc-14-261-2020}, author = {Hogan, Kelly and Martin Jakobsson and Larry A Mayer and Brendan Reilly and Jennings, A. and Stoner, J S and Nielsen, T. and Katrine J. Andresen and Kamla, E. and Kevin Jerram and Christian Stranne and Alan Mix} } @article {6947, title = {A Global Geographic Grid System for Visualizing Bathymetry}, volume = {9(2)}, year = {2020}, month = {October 7}, pages = {375-384}, publisher = {European Geosciences Union}, abstract = {

A global geographic grid system (Global GGS) is here introduced to support the display of gridded bathymetric data at whatever resolution is available in a visually seamless manner. The Global GGS combines a quadtree metagrid hierarchy with a system of compatible data grids. Metagrid nodes define the boundaries of data grids. Data grids are regular grids of depth values, coarse grids are used to represent sparse data and finer grids are used to represent high-resolution data. Both metagrids and data grids are defined in geographic coordinates to allow broad compatibility with the widest range of geospatial software packages. An important goal of the Global GGS is to support the meshing of adjacent tiles with different resolutions so as to create a seamless surface. This is accomplished by ensuring that abutting data grids either match exactly with respect to their grid-cell size or only differ by powers of 2. The oversampling of geographic data grids, which occurs towards the poles due to the convergence of meridians, is addressed by reducing the number of columns (longitude sampling) by powers of 2 at appropriate lines of latitude. In addition to the specification of the Global GGS, this paper describes a proof-of-concept implementation and some possible variants.

}, doi = {10.5194/gi-9-375-2020}, url = {https://gi.copernicus.org/articles/9/375/2020/}, author = {Colin Ware and Larry A Mayer and Paul Johnson and Martin Jakobsson and Vicki L Ferrini} } @article {6867, title = {The International Bathymetric Chart of the Arctic Ocean Version 4.0}, volume = {176(2020)}, year = {2020}, month = {June 9}, abstract = {

Bathymetry (seafloor depth), is a critical parameter providing the geospatial context for a multitude of marine scientific studies. Since 1997, the International Bathymetric Chart of the Arctic Ocean (IBCAO) has been the authoritative source of bathymetry for the Arctic Ocean. IBCAO has merged its efforts with the Nippon Foundation-GEBCO-Seabed 2030 Project, with the goal of mapping all of the oceans by 2030. Here we present the latest version (IBCAO Ver. 4.0), with more than twice the resolution (200 \× 200\ m versus 500 \× 500\ m) and with individual depth soundings constraining three times more area of the Arctic Ocean (\∼19.8\% versus 6.7\%), than the previous IBCAO Ver. 3.0 released in 2012. Modern multibeam bathymetry comprises \∼14.3\% in Ver. 4.0 compared to \∼5.4\% in Ver. 3.0. Thus, the new IBCAO Ver. 4.0 has substantially more seafloor morphological information that offers new insights into a range of submarine features and processes; for example, the improved portrayal of Greenland fjords better serves predictive modelling of the fate of the Greenland Ice Sheet.

}, doi = {https://doi.org/10.6084/m9.figshare.12369314}, author = {Martin Jakobsson and Larry A Mayer and Caroline Bringensparr} } @proceedings {6748, title = {Leveraging Predictions from NOAA{\textquoteright}s Oceanographic Forecast Models to Increase Environmental Variability Awareness in Ocean Mapping}, year = {2020}, month = {January 13-17}, address = {Boston, MA}, abstract = {
The efficient acquisition of high-quality data using modern seafloor mapping systems is too often limited by the poor awareness of the oceanographic environment in which the surveys are conducted. As such, two tools that support ocean mappers in accessing the increasingly reliable predictions from NOAA\&$\#$39;s operational 3-D oceanographic forecast modeling systems and also NOAA\&$\#$39;s World Ocean Atlas have been developed and made freely available: Sound Speed Manager and SmartMap.
Sound Speed Manager is an open-source, Python-based library and desktop application to perform accurate processing and management of sound speed profiles. Once loaded, the measured oceanographic data may be enhanced/extended using different sources (e.g. the National Ocean Service\&$\#$39;s Gulf of Maine Operational Forecast System, the National Weather Service\&$\#$39;s Global Real-Time Forecast System), validated, and exported in several file formats commonly recognized by acquisition and processing applications. The processed profiles are stored in a per-project SQLite database, and several analysis functions and tools to manage the database-stored profiles are also available.
SmartMap provides web services (and a GIS portal) that transpose publicly-available oceanographic environmental data predictions into the estimated effects on the survey data.
The adopted spatial variability analysis estimates the uncertainty using model-retrieved synthetic profiles. The data ingestion is performed using a combination of code written in Python and C++ to combine the strengths of both languages. The results, provided as a water-depth percentage of ray-tracing depth uncertainty, are useful in all the phases of a survey, from planning to the execution and processing phases. SmartMap outputs can be accessed using Open Geospatial Consortium (OGC) web services (and thus loaded as a
map layer in existing desktop GIS applications) and through a dedicated Web GIS site (https://www.hydroffice.org/smartmap/).
Ongoing research efforts for both tools are targeting the adoption of NOS\&$\#$39; operational Great Lakes, estuarine and coastal 3-D oceanographic forecast modeling systems - like the Gulf of Maine Operational Forecast System (GoMOFS) - to enhance and extend (or even substitute) the data collected on-site by sound speed profilers, and the use of the model-derived environmental uncertainty as a meaningful input to better predict profiling times.
}, doi = {https://dx.doi.org/10.13140/RG.2.2.12426.00966}, author = {Giuseppe Masetti and Larry A Mayer and Paul Johnson and John G Kelley} } @article {6869, title = {Mass Wasting on Alpha Ridge in the Arctic Ocean: New Insights from Multibeam Bathymetry and Sub-bottom Profiler Data}, volume = {500}, year = {2020}, month = {May 13}, pages = {323-340}, abstract = {

Marine geological and geophysical data from Alpha Ridge in the Arctic Ocean are sparse because of thick perennial sea-ice cover, which prevents access by most surface vessels. Rare seismic data in this area, acquired largely from drifting ice-camps, had shown the hemipelagic drape that covers most of the ridge is highly disrupted within a large (\>90 000 km2) south central region. Here, evidence of pronounced seafloor erosion and debris flows infilling seafloor lows was previously interpreted to be the result of a possible bolide impact. In recent years, several icebreaker expeditions have successfully acquired multibeam bathymetry and sub-bottom profiler data in the western segment of this region. Analysis of these data reveals a complex seafloor morphology characterized by ridges and troughs, angular blocks and escarpments as well as seismic facies characterized by hyperbolic seafloor reflections, and convoluted to incoherent and transparent sub-bottom reflectivity. These features are interpreted as evidence of sediment mass movement with varying degrees of lateral transport deformation. At least two episodes of failure are interpreted based on the presence of both buried and surficial mass-transport features. As multiple events are interpreted, seismicity is the most plausible trigger mechanism rather than bolide impact.

}, doi = {https://doi.org/10.1144/SP500-2019-196}, author = {Boggild, K. and David C Mosher and Travaglini, P.G. and Gebhardt, C. and Larry A Mayer} } @proceedings {6750, title = {Open Backscatter Toolchain (OpenBST) - A Community-Vetted Workflow for Backscatter Processing}, year = {2020}, month = {February 24-27}, address = {Quebec City, Quebec, Canada}, abstract = {

Seafloor acoustic backscatter collected by multibeam echosounders (MBES) is routinely used to generate products such as backscatter mosaics and angular response curves. However, the usability of backscatter products has been hindered by a lack of consistent outputs that may be the result of differences in sonar calibration, data collection and processing. The Open BackScatter Toolchain (OpenBST) project aims to mitigate discrepancies that arise from existing processing workflows by providing open-source, community-vetted processing algorithms for backscatter data. In this work, an example of the OpenBST approach was applied to the backscatter processing workflow for a popular multibeam echosounder, using a reference dataset recently collected in Portsmouth Harbor, NH. At each processing step, intermediate outputs are produced (and compared) using commonly adopted methodologies. Finally, an analysis of the relative relevance of selecting those methodologies at the various intermediate steps is presented.

}, keywords = {acoustic baskscatter, ocean mapping, open source, Seafloor Characterization}, doi = {https://dx.doi.org/10.13140/RG.2.2.19660.77442}, url = {https://www.conferium.com/OLM/Prg_Present.lasso?showevent=202}, author = {Michael Smith and Giuseppe Masetti and Larry A Mayer and Mashkoor A Malik and Augustin, Jean-Marie and Cyrille Poncelet and Ian Parnum} } @article {6937, title = {Ryder Glacier in Northwest Greenland is Shielded from Warm Atlantic Water by a Bathymetric Sill}, volume = {45}, year = {2020}, month = {November 4}, publisher = {Springer Nature}, abstract = {

The processes controlling advance and retreat of outlet glaciers in fjords draining the Greenland Ice Sheet remain poorly known, undermining assessments of their dynamics and associated sea-level rise in a warming climate. Mass loss of the Greenland Ice Sheet has increased six-fold over the last four decades, with discharge and melt from outlet glaciers comprising key components of this loss. Here we acquired oceanographic data and multibeam bathymetry in the previously uncharted Sherard Osborn Fjord in northwest Greenland where Ryder Glacier drains into the Arctic Ocean. Our data show that warmer subsurface water of Atlantic origin enters the fjord, but Ryder Glacier\’s floating tongue at its present location is partly protected from the inflow by a bathymetric sill located in the innermost fjord. This reduces under-ice melting of the glacier, providing insight into Ryder Glacier\’s dynamics and its vulnerability to inflow of Atlantic warmer water.

}, doi = {https://doi.org/10.1038/s43247-020-00043-0}, author = {Martin Jakobsson and Larry A Mayer and Johan Nilsson and Christian Stranne}, editor = {Brian R Calder and Matt O{\textquoteright}Regan and John Farell and Thomas M. Cronin and Volker Br{\"u}chert and Julek Chawarski and Bjorn Eriksson and Jonas Fredriksson and Laura Gemery and Anna Glueder and Felicity A. Holmes and Kevin Jerram and Nina Kirchner and Alan Mix and Julia Muchowski and Abhay Prakash and Brendan Reilly and Brett Thornton and Adam Ulfsbo and Elizabeth Weidner and Henning {\r A}kesson and Tamara Handl and Emelie St{\r a}hl and Lee-Gray Boze and Samuel Reed and Gabriel West and June Padman} } @article {6970, title = {Scientific Challenges and Present Capabilities in Underwater Robotic Vehicle Design and Navigation for Oceanographic Exploration Under-Ice}, volume = {12(16):2588}, year = {2020}, month = {August 11}, abstract = {

This paper reviews the scientific motivation and challenges, development, and use of underwater robotic vehicles designed for use in ice-covered waters, with special attention paid to the navigation systems employed for under-ice deployments. Scientific needs for routine access under fixed and moving ice by underwater robotic vehicles are reviewed in the contexts of geology and geophysics, biology, sea ice and climate, ice shelves, and seafloor mapping. The challenges of under-ice vehicle design and navigation are summarized. The paper reviews all known under-ice robotic vehicles and their associated navigation systems, categorizing them by vehicle type (tethered, untethered, hybrid, and glider) and by the type of ice they were designed for (fixed glacial or sea ice and moving sea ice).

}, doi = {https://doi.org/10.3390/rs12162588}, author = {Laughlin D.L. Barker and Jakuba, Michael and Bowen, Andrew and Christopher R. German and Maksym, Ted and Larry A Mayer and Boetius, A. and Pierre Dutrieux and Whitcomb, Louis L} } @article {6740, title = {Standardized Geomorphic Classification of Seafloor Within the United States Atlantic Canyons and Continental Margin}, volume = {7(9)}, year = {2020}, month = {January 28}, pages = {1-9}, abstract = {

Accurate seafloor maps serve as a critical component for understanding marine\ ecosystems and guiding informed ocean management decisions. From 2004 to\ 2015, the Atlantic Ocean continental margin offshore of the United States has been\ systematically mapped using multibeam sonars. This work was done in support of\ the U.S. Extended Continental Shelf (ECS) Project and for baseline characterization of\ the Atlantic canyons, but the question remains as to the relevance of these marginwide\ data sets for conservation and management decisions pertaining to these areas.\ This study utilized an automatic segmentation approach to initially identify landform\ features from the bathymetry of the region, then translated these results into complete\ coverage geomorphology maps of the region utilizing the coastal and marine ecological\ classification standard (CMECS) to define geoforms. Abyssal flats make up more than\ half of the area (53\%), with the continental slope flat class making up another 30\% of\ the total area. Flats of any geoform class (including continental shelf flats and guyot flats)\ make up 83.06\% of the study area. Slopes of any geoform class make up a cumulative\ total of 13.26\% of the study region (8.27\% abyssal slopes, 3.73\% continental slopes, and 1.25\% seamount slopes). While ridge features comprise only 1.82\% of the total\ study area (1.03\% abyssal ridges, 0.63 continental slope ridge, and 0.16\% seamount\ ridges). Key benefits of the study\’s semi-automated approach include computational\ efficiency for large datasets, and the ability to apply the same methods to large regions\ with consistent results.

}, keywords = {Atlantic, bathymorphon, classification, coastal and marine ecological classification standard, geoform, geomorphology, geomorphometry, seafloor}, doi = {10.3389/fmars.2020.00009}, url = {https://doi.org/10.3389/fmars.2020.00009}, author = {Derek Sowers and Giuseppe Masetti and Larry A Mayer and Paul Johnson and James V. Gardner and Andrew A. Armstrong} } @inbook {6969, title = {Submarine Ridges and Submarine Elevations under the Law of the Sea Convention: A Further Look}, booktitle = {New Knowledge and Changing Circumstances in the Law of the Sea}, year = {2020}, month = {August 28}, pages = {264{\textendash}288}, publisher = {Brill Nijhoff Press}, organization = {Brill Nijhoff Press}, chapter = {13}, abstract = {

This Chapter presents a legal analysis of paragraph 6 of article 76 of the United Nations Convention on the Law of the Sea. This paragraph sets forth rules for determining the outer limits of a coastal State\’s continental shelf on \“submarine ridges\” and \“submarine elevations.\” Because its provisions are complex and not clearly drafted, paragraph 6 has proven challenging to interpret and apply for both coastal States and the Commission on the Limits of the Continental Shelf. This Chapter examines alternative interpretations of this paragraph, and suggests an interpretation that would put the Commission\’s future recommendations on firmer legal footing.

}, doi = {https://doi.org/10.1163/9789004437753_015}, author = {Kevin A. Baumert and Larry A Mayer}, editor = {Tomas Heidar} } @article {6933, title = {Tracking the Spatiotemporal Variability of the Oxic{\textendash}Anoxic Interface in the Baltic Sea with Broadband Acoustics}, year = {2020}, month = {03 November 2020}, abstract = {

Anoxic zones, regions of the water column completely devoid of dissolved oxygen, occur in open oceans and coastal zones worldwide. The Baltic Sea is characterized by strong salinity-driven stratification, maintained by occasional water inflows from the Danish Straights and freshwater input from rivers. Between inflow events, the stratification interface between surface and deep waters hinders mixing and ventilation of deep water; consequently, the bottom waters of large regions of the Baltic are anoxic. The onset of the anoxic zone is closely coincident with the depth of the halocline and, as a result, the interface between oxic and anoxic waters corresponds to a strong impedance contrast. Here, we track acoustic scattering from the impedance contrast utilizing a broadband split-beam echosounder in the Western Gotland Basin and link it to a dissolved oxygen level of 2 ml/l using ground truth stations. The broadband acoustic dataset provides the means to remotely observe the spatiotemporal variations in the oxic\–anoxic interface, map out the extent of the anoxic zone with high resolution, and identify several mechanisms influencing the vertical distribution of oxygen in the water column. The method described here can be used to study other systems with applications in ongoing oceanographic monitoring programs.

}, keywords = {anoxia, Baltic Sea, Broadband acoustics, climate change, coastal, hypoxia, stratification}, doi = {10.1093/icesjms/fsaa153}, url = {https://academic.oup.com/icesjms/advance-article/doi/10.1093/icesjms/fsaa153/5952886?guestAccessKey=a0ae8696-7215-4e71-a8c5-bbd38fbb1a77}, author = {Elizabeth Weidner and Christian Stranne and Jonas Henati Sundberg and Thomas C Weber and Larry A Mayer and Martin Jakobsson} } @article {6703, title = {Adding Value to Broad-Scale Ocean Exploration Mapping Data Through Standardized Geomorphic Classification and Backscatter Data Analysis}, year = {2019}, month = {December 9-13}, pages = {San Francisco, CA}, abstract = {

Accurate maps of ocean bathymetry and seafloor habitats serve as a fundamental basis for understanding marine ecosystems and guiding marine spatial planning efforts. From 2004-2015, a vast region of the Atlantic Ocean continental margin offshore of the United States has been systematically mapped using multibeam sonars in support of the U.S. Extended Continental Shelf (ECS) Project and for baseline characterization of the Atlantic canyons. Now that these high cost and high quality datasets have been collected, there is a rich opportunity to further analyze and interpret these data to generate value-added spatial datasets on seafloor geomorphology, substrate, and potential habitat suitability for deep sea biota. This study presents a methodology to generate geomorphology and predicted substrate spatial datasets using semi-automated classification methods that are transparent and repeatable, and utilizing a standardized classification scheme (the Coastal and Marine Ecological Classification Standard - CMECS). \ The approach developed through this work provides a model of how to consistently classify seafloor attributes using CMECS as an organizing framework across large potential regions nationally or globally.

This study utilized an automatic segmentation approach to identify landform features from the bathymetry of the region, then translated these results into complete coverage geomorphology (CMECS geoform component) maps of the region. Results provide a characterization of the marine landscape that serves as an inventory of the cumulative area and abundance of geoforms and the spatial relationships among them. Geoform summary statistics were calculated over the study region to quantify the area of each geoform type. These analyses represent a first step in identifying regions of consistent morphology within which the consistency of the backscatter can then be determined. Detailed analysis of the backscatter response for insights into predicted substrate types within the region represents the next phase of the study, and preliminary results will be presented. Key benefits of the study\’s semi-automated approach include computational efficiency for large datasets, and the ability to apply the same methods to large regions with consistent results.

}, author = {Derek Sowers and Giuseppe Masetti and Larry A Mayer and Paul Johnson and James V. Gardner and Andrew A. Armstrong} } @article {6803, title = {Echoes from the Ocean{\textquoteright}s Interior: High-Frequency Observations of Ocean Phenomena}, volume = {145(3)}, year = {2019}, month = {April 23}, pages = {1653-1653}, publisher = {Acoustical Society of America}, abstract = {

Recent technological advances in high-frequency (\>10 kHz) sonar transducers, sonar transceivers, and sonar design have been accompanied by increased capabilities for observing ocean phenomena. These advances include the high range resolution and frequency-domain target classification capabilities associated with wideband acoustic echo sounders, the long-range high-resolution synoptic imaging capabilities associated with multibeam echo sounders and synthetic aperture sonar, and an increased focus on sensor calibration for all systems. High-frequency sonars are increasingly being used to quantify ocean phenomena at scales ranging from sub-centimeter (e.g., individual gas bubbles) to 100s of km (e.g., internal waves) to several 10s of km (e.g., thermohaline staircases). In this talk, we highlight some of the ocean processes that we have been investigating using high-frequency sonar systems, typically involving the transport of hydrocarbons, heat, energy, and fresh water into and through the ocean, and some of the (many) acoustic challenges that must be overcome to continue to increase the value of these observations.

}, doi = {10.1121/1.5101062}, author = {Thomas C Weber and Larry A Mayer and Anthony P. Lyons and Loranger, Scott and Alexandra M Padilla and Elizabeth Weidner} } @article {6826, title = {Evolving Arctic Bathymetry: The International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 4.0 Compiled Under the Auspices of the Nippon Foundation-GEBCO-Seabed 2030 Project}, year = {2019}, month = {December 9-13}, pages = {San Francisco, CA}, abstract = {

The International Bathymetric Chart of the Arctic Ocean (IBCAO) project was initiated in 1997 to meet the need for up-to-date digital portrayals of the Arctic Ocean seafloor. The original international effort assembled all available Arctic bathymetric data and gridded them using a continuous curvature spline under tension at a resolution of 2.5 x 2.5 km to produce a Digital Bathymetric Model (DBM). The resulting DBM, compiled on a Polar Stereographic Projection, was unprecedented in its ability to depict the complexities of Arctic bathymetry and has provided the geospatial context for countless scientific studies. Since the initial IBCAO DBM (Ver. 1.0), two more versions have been published. Ver. 2.0, at 2 x 2 km resolution and Ver. 3 with 500 x 500 m resolution. In all cases, many data sources including multi- and single-beam bathymetry as well as contours and soundings digitized from depth charts were incorporated following the concept developed for IBCAO Ver. 1, where direct depth observations get the highest priority and digitized contours the lowest. Recently the IBCAO project has merged its efforts with the Nippon Foundation-GEBCO-Seabed 2030 Project, an international effort whose goal it is to see the entire world ocean mapped by 2030. Working under the auspices of the Seabed 2030 program (but maintaining the its well-recognized identity) we now introduce IBCAO Ver. 4, compiled using a refined gridding algorithm compared to previous versions and with nearly three times more area of the Arctic Ocean constrained by bathymetric data relative to Ver. 3.0. In preparation for the eventual production of a multi-resolution grid that changes resolution with water depth to reflect achievable resolution from surface vessels, Ver. 4 has been created at a 100\×100 m grid spacing, using a pyramidal scheme of assembling the data considering its native resolution. This results in a degree of oversampling where the native resolution does not justify a 100 m grid, but in those regions where this resolution is achievable (e.g. depths less than say 1500-2000 m) the higher resolution allows analyses and regional uses that previously were not possible, including the depiction of megascale glacial lineations, large pock-marks and the dynamics of newly discovered Arctic submarine channels.

}, url = {https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/575093}, author = {Martin Jakobsson and Larry A Mayer} } @article {6718, title = {Mapping Multibeam Echo Sounders {\textendash} A Square Peg in a Round Hole}, volume = {14}, year = {2019}, month = {Fall}, pages = {41-46}, publisher = {Fisheries and Marine Institute of Memorial University of Newfoundland}, author = {Hilary Kates Varghese and Michael Smith and Jennifer Miksis-Olds and Larry A Mayer} } @article {6626, title = {Mapping the Lava Deltas of the 2018 Eruption of Kilauea Volcano}, volume = {32(1)}, year = {2019}, month = {March}, pages = {46-47}, publisher = {The Oceanography Society}, abstract = {

Kilauea on the Island of Hawai\‘i is one of the most active\ and well-monitored volcanoes in the world. Its most devastating eruption of the last 200 years occurred in 2018,\ destroying more than 700 homes and other structures\ and displacing thousands of residents (Hawaiian Volcano\ Observatory Staff, 2018). As is common for Hawaiian eruptions, the lava flows from the 2018 lower East Rift Zone\ reached the coastline, where they produced prodigious\ plumes of toxic, corrosive steam and several spectacular hydrovolcanic explosions. As activity progressed, a\ significant volume of lava entered the ocean and was\ deposited on Kilauea\’s submarine slopes, where it formed\ a lava delta. Through funding provided by NOAA\’s Office of\ Ocean Exploration and Research and the National Science\ Foundation\’s Ocean Sciences Division, scientists aboard\ E/V Nautilus mapped the south flank of Kilauea with the\ ship\’s EM 302 multibeam echosounder to characterize this and other recently formed lava deltas.

}, doi = {https://doi.org/10.5670/oceanog.2019.supplement.01}, url = {http://tos.org/oceanography/assets/docs/32-1_supplement.pdf?fbclid=IwAR0F2Vvb96e-GHS8GGGbESuK8qoPSHu76O0FlLAKb65smE_OJ8xyNCyUPaU}, author = {Soule, S A and Erin Heffron and Lindsay Gee and Larry A Mayer and Nicole A Raineault and Christopher R. German and Lim, Darlene S.S. and Zoeller, Michael and Parcheta, Carolyn} } @article {6517, title = {The Open Backscatter Toolchain (OpenBST) Project: Towards an Open-Source and Metadata-Rich Modular Implementation}, year = {2019}, month = {March 18-21}, pages = {Biloxi, MS}, abstract = {

Most ocean mapping surveys collect seafloor reflectivity (backscatter) along with bathymetry. While the consistency of bathymetry processed by commonly adopted algorithms is well established, surprisingly large variability is observed between the backscatter mosaics generated by different software packages when processing the same dataset. Such a situation severely limits the use of acoustic backscatter for quantitative analysis (e.g., monitoring seafloor change over time, or remote characterization of seafloor characteristics) and other commonly attempted tasks (e.g., merging mosaics from different origins).

Acoustic backscatter processing involves a complex sequence of steps, but inasmuch as commercial software packages mainly provide end-results, comparisons between those results offer little insight into where in the workflow the differences are generated. In addition, preliminary results of a software-inter-comparison working group have shown that each processing algorithm tends to adopt a distinct, unique workflow; this causes large disagreements even in the initial per-beam reflectivity values resulting from differences in basic operations such as snippet averaging and evaluation of flagged beams.

Far from ideal, this situation requires a clear shift from the past closed-source approach that has caused it. As such, the Open Backscatter Toolchain (OpenBST) project aims to provide the community with an open-source and metadata-rich modular implementation of a toolchain dedicated to acoustic backscatter processing. The long-term goal is not to create processing tools that would compete with available commercial solutions, but rather a set of open-source, community-vetted, reference algorithms usable by both developers and users for benchmarking their processing algorithms.

As a proof-of-concept, we present a prototype implementation with the key elements of the OpenBST approach:

The data conversion from a native acquisition format (i.e., Kongsberg EM Series) to NetCDF-based data structures (components of the eXtensible Sounder Format) better suited to data exploration, processing and metadata coupling.

A processing pipeline constituted by a set of interlocking, task-oriented tools simplifying their substitution with alternative approaches.

The creation of final products (i.e., angular response curves and backscatter mosaics) capturing relevant acquisition and processing metadata.

}, keywords = {Acoustic backscatter, angular response analysis, multibeam echosounder, software intercomparison}, doi = {10.13140/RG.2.2.19336.67849}, url = {https://www.researchgate.net/publication/331965414_The_Open_Backscatter_Toolchain_OpenBST_project_towards_an_open-source_and_metadata-rich_modular_implementation}, author = {Giuseppe Masetti and Augustin, Jean-Marie and Mashkoor A Malik and Cyrille Poncelet and Xavier Lurton and Larry A Mayer and Glen A Rice and Michael Smith} } @article {6613, title = {Seafloor Mapping {\textendash} The Challenge of a Truly Global Ocean Bathymetry}, volume = {6(283)}, year = {2019}, month = {June 5}, pages = {283}, abstract = {

Detailed knowledge of the shape of the seafloor is crucial to humankind. Bathymetry data is critical for safety of navigation and is used for many other applications. In an era of ongoing environmental degradation worldwide, bathymetry data (and the knowledge derived from it) play a pivotal role in using and managing the world\’s oceans in a way that is in accordance with the United Nations Sustainable Development Goal 14 \– conserve and sustainably use the oceans, seas and marine resources for sustainable development. However, the vast majority of our oceans is still virtually unmapped, unobserved, and unexplored. Only a small fraction of the seafloor has been systematically mapped by direct measurement. The remaining bathymetry is predicted from satellite altimeter data, providing only an approximate estimation of the shape of the seafloor. Several global and regional initiatives are underway to change this situation. This paper presents a selection of these initiatives as best practice examples for bathymetry data collection, compilation and open data sharing as well as the Nippon Foundation-GEBCO (The General Bathymetric Chart of the Oceans) Seabed 2030 Project that complements and leverages these initiatives and promotes international collaboration and partnership. Several non-traditional data collection opportunities are looked at that are currently gaining momentum as well as new and innovative technologies that can increase the efficiency of collecting bathymetric data. Finally, recommendations are given toward a possible way forward into the future of seafloor mapping and toward achieving the goal of a truly global ocean bathymetry.

}, doi = {https://doi.org/10.3389/fmars.2019.00283}, url = {https://www.frontiersin.org/articles/10.3389/fmars.2019.00283/full}, author = {Anne-Cathrin W{\"o}lfl and Helen Snaith and Amirebrahim, Sam and Devey, Colin W. and Dorschel, B. and Vicki L Ferrini and Huvenne, Veerle A.I. and Martin Jakobsson and Jennifer Jencks and Johnston, Gordon and Geoffroy Lamarche and Larry A Mayer and Millar, David and Pedersen, Terje and Picard, Kim and Reitz, Anja and Schmitt, Thierry and Visbeck, Martin and Pauline Weatherall and Rochelle Wigley} } @proceedings {6598, title = {Sensing for Hydrographic Autonomous Surface Vehicles}, year = {2019}, month = {March 19-21}, publisher = {The Hydrographic Society of America}, address = {Biloxi, MS}, abstract = {

With increasing interest in the use of autonomous surface vessels (ASVs) to automate hydrographic data collection in support of safe navigation, there is a growing likelihood that ASVs will be operated in regions with uncertain or limited prior knowledge of where it is safe to navigate. In addition to this challenge, coastal environments may have significant boat traffic and other hazards for an unmanned vehicle, such as buoys, lobster pots and kelp. If ASVs are to operate safely and truly autonomously, means must be developed to increase the awareness of the ASV to its environment so that it can safely maneuver with minimal operator intervention.

This paper provides a review of a variety of sensing systems used by ASVs for the identification of obstacles on the surface and underwater, their detection and classification capabilities, and their limitations and uncertainties. AIS, radar, LiDAR, color and infrared (FLIR) cameras, multibeam echo-sounders and forward looking sonar are considered. The paper will explore how to use the complementary nature of these sensors in order to offer the best possible environmental perception and situational awareness. In addition, the paper will look at a number of obstacle types, evaluate their detection requirements, and match these requirements with the sensors available aboard the ASV, including the determination of which sensors provide actionable information natively, and which require further algorithm development. Finally, the use of deep learning algorithms will be examined using data from the ASV\’s camera to better understand the applicability of deep learning for the detection of objects in the marine environment.

}, keywords = {asv, Autonomous Survey Systems, Sensor Fusion}, author = {Coral Moreno and Val Schmidt and Brian R Calder and Larry A Mayer} } @article {6627, title = {{\textquotedblleft}Walking with the Ancients{\textquotedblright} in the Southern California Continental Borderland}, volume = {vol. 32(1)}, year = {2019}, month = {March 1}, pages = {54-55}, publisher = {The Oceanography Society}, abstract = {

\“Walking with the Ancients\” was the fifth in a series of\ E/V Nautilus expeditions to the Channel Islands and the\ Southern California Continental Borderland that began in\ 2016. Cruise sponsors were NOAA\’s Office of Ocean Exploration and Research, the Office of Naval Research, the National\ Geographic Society, and the Lounsbery Foundation. The primary focus of the five expeditions was to discover and investigate submerged caves carved by the sea since the Last Glacial Maximum (LGM) some 19,000 years ago. When the great continental ice sheets began to melt,\ sea level rose discontinuously, creating a series of paleoshorelines.\ 

}, doi = {https://doi.org/10.5670/oceanog.2019.supplement.01}, url = {http://tos.org/oceanography/assets/docs/32-1_supplement.pdf?fbclid=IwAR0F2Vvb96e-GHS8GGGbESuK8qoPSHu76O0FlLAKb65smE_OJ8xyNCyUPaU}, author = {Robert Ballard and Larry A Mayer and Kenneth Broad and Coleman, D. F. and Erin Heffron and Val Schmidt} } @article {6494, title = {A Wideband Acoustic Method for Direct Assessment of Bubble-Mediated Methane Flux}, volume = {173}, year = {2019}, month = {February 1}, pages = {104-115}, publisher = {Elsevier}, abstract = {

The bubble-mediated transport and eventual fate of methane escaping from the seafloor is of great interest to researchers in many fields. Acoustic systems are frequently used to study gas seep sites, as they provide broad synoptic observations of processes in the water column. However, the visualization and characterization of individual gas bubbles needed for quantitative studies has routinely required the use of optical sensors which offer a limited field of view and require extended amounts of time for deployment and data collection. In this paper, we present an innovative method for studying individual bubbles and estimating gas flux using a calibrated wideband split-beam echosounder. The extended bandwidth (16 \– 26 kHz) affords vertical range resolution of approximately 7.5 cm, allowing for the differentiation of individual bubbles in acoustic data. Split-aperture processing provides phase-angle data used to compensate for transducer beam-pattern effects and to precisely locate bubbles in the transducer field of view. The target strength of individual bubbles is measured and compared to an analytical scattering model to estimate bubble radius, and bubbles are tracked through the water column to estimate rise velocity. The resulting range of bubble radii (0.68\–8.40 mm in radius) agrees with those found in other investigations with optical measurements, and the rise velocities trends are consistent with published models. Together, the observations of bubble radius and rise velocity offer a measure of gas flux, requiring nothing more than vessel transit over a seep site, bypassing the need to deploy time-consuming and expensive optical systems.

}, keywords = {Broadband acoustics, Bubble fate, East Siberian Arctic Ocean, Ebullition, Gas flux, Methane gas bubbles, swerus-c3}, doi = {https://doi.org/10.1016/j.csr.2018.12.005}, url = {https://www.sciencedirect.com/science/article/pii/S0278434318303649?via\%3Dihub}, author = {Elizabeth Weidner and Thomas C Weber and Larry A Mayer and Martin Jakobsson and Denis Chemykh and Semiltov, I.} } @article {6345, title = {Acoustic Mapping of Mixed Layer Depth}, volume = {14, 3}, year = {2018}, month = {June 22}, pages = {503-514}, abstract = {

The ocean surface mixed layer is a nearly universal feature of the world oceans. Variations in the depth of the mixed layer (MLD) influences the exchange of heat, fresh water (through evaporation), and gases between the atmosphere and the ocean and constitutes one of the major factors controlling ocean primary production as it affects the vertical distribution of biological and chemical components in near-surface waters. Direct observations of the MLD are traditionally made by means of conductivity, temperature, and depth (CTD) casts. However, CTD instrument deployment limits the observation of temporal and spatial variability in the MLD. Here, we present an alternative method in which acoustic mapping of the MLD is done remotely by means of commercially available ship-mounted echo sounders. The method is shown to be highly accurate when the MLD is well defined and biological scattering does not dominate the acoustic returns. These prerequisites are often met in the open ocean and it is shown that the method is successful in 95 \% of data collected in the central Arctic Ocean. The primary advantages of acoustically mapping the MLD over CTD measurements are (1) considerably higher temporal and horizontal resolutions and (2) potentially larger spatial coverage.

}, doi = {10.5194/os-14-503-2018}, url = {https://www.ocean-sci.net/14/503/2018/os-14-503-2018-discussion.html}, author = {Christian Stranne and Larry A Mayer and Martin Jakobsson and Elizabeth Weidner and Kevin Jerram and Thomas C Weber and Andersson, Leif and Johan Nilsson and Bjork, G and Katarina G{\r a}rdfeldt} } @article {6495, title = {An Automatic Procedure for the Quantitative Characterization of Submarine Bedforms}, volume = {8(1)}, year = {2018}, month = {January 21}, pages = {28}, publisher = {MDPI}, abstract = {

A model for the extraction and quantitative characterization of submarine landforms from high-resolution digital bathymetry is presented. The procedure is fully automated and comprises two parts. The first part consists of an analytical model which extracts quantitative information from a Digital Elevation Model in the form of objects with similar parametric characteristics (terrain objects). The second part is a rule-based model where the terrain objects are reclassified into distinct landforms with well-defined three dimensional characteristics. For the focus of this work, the quantitative characterization of isolated dunes (height greater than 2 m) is used to exemplify the process. The primary metrics used to extract terrain objects are the flatness threshold and the search radius, which are then used by the analytical model to identify the feature type. Once identified as dunes, a sequence of spatial analysis routines is applied to identify and compute metrics for each dune including length, height, width, ray of curvature, slope analysis for each stoss and lee side, and dune symmetry. Dividing the model into two parts, one scale-dependent and another centered around the shape of the landform, makes the model applicable to other submarine landforms like ripples, mega-ripples, and coral reefs, which also have well-defined three-dimensional characteristics.

}, doi = {https://doi.org/10.3390/geosciences8010028 }, url = {https://www.mdpi.com/2076-3263/8/1/28}, author = {Massimo Di Stefano and Larry A Mayer} } @article {6309, title = {Bathymetric and Reflectivity-derived Data Fusion for Preliminary Seafloor Segmentation and Strategic Bottom Sampling}, year = {2018}, month = {May 7-11}, pages = {Santa Barbara, CA}, abstract = {

Modern multibeam sonars and processing software typically produce geo-located bathymetry and backscatter mosaic products, thus offering the opportunity to treat both data sets together to support seafloor characterization. However, there are few studies that have offered general methods for using machine-focused (automated) approaches for seafloor segmentation that combine and use the information found in co-located bathymetric digital elevation models (DEMs) and acoustic reflectivity mosaics.

We explore a methodology to combine both bathymetry and backscatter data to automatically segment the seafloor. The proposed method attempts to mimic the approach taken by a skilled analyst assuming that, when called upon to manually segment a seafloor area, the analyst initially evaluates the context surrounding the area and attempts to take full advantage of both bathymetric and reflectivity products rather than focusing on small-scale geomorphometric variability (e.g., local rugosity). The result is a bathymetry- and reflectivity-based estimator for seafloor segmentation that mimics the positive aspects of the segmentation process as performed by a skilled analyst (e.g., the use of context and multiple inputs) but avoids the inherent deficiencies (subjectivity, processing time, lack of reproducibility).

The algorithm starts by adopting principles of topographic openness, pattern recognition, and texture classification to identify geomorphic elements of the seafloor or \“area kernels\”, and then derives the final seafloor segmentation by merging or splitting the kernels based on the principles of similarity and multi-modality.

The output is a collection of preliminary, homogeneous, non-overlapping seafloor segments of consistent morphology and acoustic backscatter texture. Each labeled segment is enriched by a list of derived, physically-meaningful attributes that can be used for subsequent task-specific analysis. In this work, the resulting segments have been evaluated as possible inputs to identify a strategic seafloor sampling (ground-truthing) plan aimed at advancing characterization results while optimizing operational field efforts.

}, keywords = {seafloor segmentation, strategic bottom sampling}, url = {https://www.geohab2018.org/program}, author = {Giuseppe Masetti and Larry A Mayer and Larry G Ward and Derek Sowers} } @article {6235, title = {Bathymetry and Oceanic Flow Structure at Two Deep Passages Crossing the Lomonosov Ridge}, volume = {14}, year = {2018}, month = {January 2}, pages = {1-13}, publisher = {Copernicus Publications}, abstract = {

The Lomonosov Ridge represents a major topographical feature in the Arctic Ocean which has a large effect on the water circulation and the distribution of water properties. This study presents detailed bathymetric survey data along with hydrographic data at two deep passages across the ridge: A southern passage (80\–81\°\ N) where the ridge crest meets the Siberian continental slope and a northern passage around 84.5\°\ N. The southern channel is characterized by smooth and flat bathymetry around 1600\–1700\ m with a sill depth slightly shallower than 1700\ m. A hydrographic section across the channel reveals an eastward flow with Amundsen Basin properties in the southern part and a westward flow of Makarov Basin properties in the northern part. The northern passage includes an approximately 72\ km long and 33\ km wide trough which forms an intra basin in the Lomonosov Ridge morphology (the Oden Trough). The eastern side of Oden Trough is enclosed by a narrow and steep ridge rising 500\–600\ m above a generally 1600\ m deep trough bottom. The deepest passage (the sill) is 1470\ m deep and located on this ridge. Hydrographic data show irregular temperature and salinity profiles indicating that water exchange occurs as midwater intrusions bringing water properties from each side of the ridge in well-defined but irregular layers. There is also morphological evidence that some rather energetic flows may occur in the vicinity of the sill. A well expressed deepening near the sill may be the result of seabed erosion by bottom currents.

}, doi = {doi.org/10.5194/os-2017-14}, author = {Bjork, G and Martin Jakobsson and Assmann, Karen and Andersson, Leif and Johan Nilsson and Christian Stranne and Larry A Mayer} } @article {6248, title = {A Bathymetry- and Reflectivity-Based Approach for Seafloor Segmentation}, volume = {8 (1)}, year = {2018}, month = {January 8}, pages = {14}, publisher = {MDPI Publishing}, address = {Basel, Switzerland}, abstract = {

A robust and flexible technique to segment seafloor acoustic mapping data by analyzing co-located bathymetric digital elevation models and acoustic backscatter mosaics is presented. The algorithm first uses principles of topographic openness, pattern recognition, and texture classification to identify geomorphic elements of the seafloor or \“area kernels\”, and then derives the final seafloor segmentation by merging or splitting the kernels based on principles of similarity and multi-modality. The output is a collection of homogeneous, non-overlapping seafloor segments of consistent morphology and acoustic backscatter texture. Each labeled segment is enriched by a list of derived, physically-meaningful attributes that can be used for subsequent task-specific analysis.

}, keywords = {Acoustic applications, object segmentation, seafloor, underwater acoustics}, doi = {10.3390/geosciences8010014}, url = {http://www.mdpi.com/2076-3263/8/1/14}, author = {Giuseppe Masetti and Larry A Mayer and Larry G Ward} } @article {6443, title = {E/V Nautilus Mapping and Exploration of North Pacific Seamounts During Expeditions in 2017 and 2018}, year = {2018}, month = {December 10-14}, pages = {Washington, DC}, abstract = {

The expeditions of Exploration Vessel (E/V) Nautilus for 2017 and 2018 covered wide areas of the North Pacific - ranging from south of the eastern end of the Clarion Fracture Zone, the Davidson Seamount within the borders of Monterey Bay National Marine Sanctuary, the SGaan Kinghlas-Bowie Seamount Marine Protected Area in northern Canadian waters, and west to the Papah{\={a}}naumoku{\={a}}kea Marine National Monument. A number of these expeditions investigated some of the seamounts that exist throughout the North Pacific.

Satellite derived maps of the seafloor have revealed tens of thousands of seamounts that rise more than 1,000m or more from the seafloor. However the vast majority have not been mapped with traditional acoustic multibeam sonar and even fewer have been explored by direct observation and sampling. The number and range of seamounts are significant in understanding the oceanic seafloor processes and the variations in the plate volcanic activity. They also support some unique ecological communities, and detailed knowledge of their shape and location assists in modelling global oceanographic circulation models.

E/V Nautilus mapped the seamounts with the Kongsberg EM302 multibeam sonar and resulting sonar bathymetry and backscatter revealed significant details of their structure and variation. The high-resolution mapping revealed considerable differences in minimum depth (+/- hundreds of meters) and areal extent of some of the seamounts from the satellite maps and added to the baseline knowledge of these significant oceanic features.

An interdisciplinary team of scien\­tists participated in the ROV dives of Hercules and Argus at sea and were supported from many institutions ashore via telepresence. The ROV dives to these unexplored seamounts included visual survey transects with limited sampling of the geology and biology. The Nautilus Science Communicators also extended engagement to the public via telepresence during all the ROV dives.

}, keywords = {e/v nautilus, exploration, mapping, Ocean Exploration Trust, Pacific, seamounts}, url = {https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/432876}, author = {Lindsay Gee and Cherisse Du Preez and Tammy Norgard and Larry A Mayer and Christopher Kelley and Chad King and Renato Kane and Erin Heffron and Nicole A Raineault} } @article {6496, title = {A Framework to Quantify Uncertainties of Seafloor Backscatter from Swath Mapping Echosounders}, volume = {39(1-2)}, year = {2018}, month = {June 1}, pages = {151-168}, publisher = {Springer}, abstract = {

Multibeam echosounders (MBES) have become a widely used acoustic remote sensing tool to map and study the seafloor, providing co-located bathymetry and seafloor backscatter. Although the uncertainty associated with MBES-derived bathymetric data has been studied extensively, the question of backscatter uncertainty has been addressed only minimally and hinders the quantitative use of MBES seafloor backscatter. This paper explores approaches to identifying uncertainty sources associated with MBES-derived backscatter measurements. The major sources of uncertainty are catalogued and the magnitudes of their relative contributions to the backscatter uncertainty budget are evaluated. These major uncertainty sources include seafloor insonified area (1\–3 dB), absorption coefficient (up to \>\ 6 dB), random fluctuations in echo level (5.5 dB for a Rayleigh distribution), and sonar calibration (device dependent). The magnitudes of these uncertainty sources vary based on how these effects are compensated for during data acquisition and processing. Various cases (no compensation, partial compensation and full compensation) for seafloor insonified area, transmission losses and random fluctuations were modeled to estimate their uncertainties in different scenarios. Uncertainty related to the seafloor insonified area can be reduced significantly by accounting for seafloor slope during backscatter processing while transmission losses can be constrained by collecting full water column absorption coefficient profiles (temperature and salinity profiles). To reduce random fluctuations to below 1 dB, at least 20 samples are recommended to be used while computing mean values. The estimation of uncertainty in backscatter measurements is constrained by the fact that not all instrumental components are characterized and documented sufficiently for commercially available MBES. Further involvement from manufacturers in providing this essential information is critically required.

}, keywords = {calibration, Incidence angle, multibeam echosounder}, doi = {https://doi.org/10.1007/s11001-018-9346-7}, url = {https://link.springer.com/article/10.1007\%2Fs11001-018-9346-7}, author = {Mashkoor A Malik and Xavier Lurton and Larry A Mayer} } @article {6329, title = {The Holocene Retreat Dynamics and Stability of Petermann Glacier in Northwest Greenland}, year = {2018}, month = {May 29}, publisher = {Springer Nature}, abstract = {

Submarine glacial landforms in fjords are imprints of the dynamic behaviour of marine-terminating glaciers and are informative about their most recent retreat phase. Here we use detailed multibeam bathymetry to map glacial landforms in Petermann Fjord and Nares Strait, northwestern Greenland. A large grounding-zone wedge (GZW) demonstrates that Petermann Glacier stabilised at the fjord mouth for a considerable time, likely buttressed by an ice shelf. This stability was followed by successive backstepping of the ice margin down the GZW\’s retrograde backslope forming small retreat ridges to 680\ m current depth (\∼730\–800\ m palaeodepth). Iceberg ploughmarks occurring somewhat deeper show that thick, grounded ice persisted to these water depths before final breakup occurred. The palaeodepth limit of the recessional moraines is consistent with final collapse driven by marine ice cliff instability (MICI) with retreat to the next stable position located underneath the present Petermann ice tongue, where the seafloor is unmapped.

}, keywords = {Arctic Ocean, cryospheric science, geomorphology}, doi = {10.1038/s41467-018-04573-2}, url = {https://www.nature.com/articles/s41467-018-04573-2}, author = {Martin Jakobsson and Hogan, Kelly and Larry A Mayer}, editor = {Mix, A C and Jennings, A. and Stoner, J S and Bjorn Eriksson and Kevin Jerram and Mohammad, R. and Pearce, Christof and Reilly, B. and Christian Stranne} } @article {6484, title = {Mapping Community Structure of Canyons and Seamounts of the Northeastern US Atlantic Margin}, year = {2018}, month = {September 9-14}, pages = {Monterey Bay, CA}, abstract = {

The deep sea communities along the continental margin of the Northeastern United States and the New England Seamount Chain are
biologically diverse systems in which little is known of their distribution and the factors that influence their distribution. In the present study, we examined the distribution and structure of benthic communities along and between ROV tracks and examined relationships between abiotic factors and habitat structure. We analyzed full underwater video footage of 5 canyons and 5 seamounts spanning depths between ~550 m and 2500 m. Tracks were collected by ROV Deep Discoverer during three cruise legs of the 2013-2014 NOAA vessel Okeanos Explorer expeditions along the Atlantic Continental margin. During each dive, a CTD recorded temperature, dissolved oxygen, salinity and depth. We then combined ROV coordinates with CTD, sediment and biological data to map the distribution of benthic communities and their associated environments. To standardize video interpretation, each track was divided into 50 m
longitudinal X 50 cm segments widths and were analyzed for substrate type and organisms. Our findings indicate both coarse and fine-scale difference in community structure between canyons and seamounts, with greater abundance of organisms in canyons and greater evenness and diversity associated to seamounts. Our correlations of abiotic factors and community structure indicate that dissolved oxygen and salinity concentrations were linked to greater evenness and dissolved oxygen concentrations with diversity of organisms for both canyons and seamounts.

}, author = {Jennifer A. Dijkstra and Kristen Mello and Mashkoor A Malik and Derek Sowers and Larry A Mayer} } @article {6399, title = {Mapping the World{\textquoteright}s Oceans}, volume = {48 (3)}, year = {2018}, month = {September 18}, pages = {35-42}, publisher = {National Academy of Engineering}, url = {https://www.nae.edu/Publications/Bridge/195218/195298.aspx}, author = {Larry A Mayer} } @article {6300, title = {The Nippon Foundation-GEBCO Seabed 2030 Project: The Quest to See the World{\textquoteright}s Oceans Completely Mapped by 2030}, volume = {8 (2)}, year = {2018}, month = {February 8}, abstract = {

Despite many of years of mapping effort, only a small fraction of the world ocean\’s seafloor has been sampled for depth, greatly limiting our ability to explore and understand critical ocean and seafloor processes. Recognizing this poor state of our knowledge of ocean depths and the critical role such knowledge plays in understanding and maintaining our planet, GEBCO and the Nippon Foundation have joined forces to establish the Nippon Foundation GEBCO Seabed 2030 Project, an international effort with the objective of facilitating the complete mapping of the world ocean by 2030. The Seabed 2030 Project will establish globally distributed regional data assembly and coordination centers (RDACCs) that will identify existing data from their assigned regions that are not currently in publicly available databases and seek to make these data available. They will develop protocols for data collection (including resolution goals) and common software and other tools to assemble and attribute appropriate metadata as they assimilate regional grids using standardized techniques. A Global Data Assembly and Coordination Center (GDACC) will integrate the regional grids into a global grid and distribute to users world-wide. The GDACC will also act as the central focal point for the coordination of common data standards and processing tools as well as the outreach coordinator for Seabed 2030 efforts. The GDACC and RDACCs will collaborate with existing data centers and bathymetric compilation efforts. Finally, the Nippon Foundation GEBCO Seabed 2030 Project will encourage and help coordinate and track new survey efforts and facilitate the development of new and innovative technologies that can increase the efficiency of seafloor mapping and thus make the ambitious goals of Seabed 2030 more likely to be achieved.

}, keywords = {global bathymetry; Seabed 2030; Nippon Foundation/GEBCO; seafloor mapping technologies; seafloor mapping standards and protocols}, doi = {10.3390/geosciences8020063}, url = {http://www.mdpi.com/2076-3263/8/2/63}, author = {Larry A Mayer and Martin Jakobsson and Allen, Graham and Dorschel, B. and Falconer, Robin and Vicki L Ferrini and Geoffroy Lamarche and Helen Snaith and Pauline Weatherall} } @article {6389, title = {Seal Occurrence and Habitat Use during Summer in Petermann Fjord, Northwestern Greenland}, volume = {71(3):334}, year = {2018}, month = {September}, publisher = {Arctic Institute of North America}, abstract = {

Ice-associated seals are considered especially susceptible and are potentially the first to modify distribution and habitat use in response to physical changes associated with the changing climate. Petermann Glacier, part of a unique ice-tongue fjord environment in a rarely studied region of northwestern Greenland, lost substantial sections of its ice tongue during major 2010 and 2012 calving events. As a result, changes in seal habitat may have occurred. Seal occurrence and distribution data were collected in Petermann Fjord and adjacent Nares Strait region over 27 days (2 to 28 August) during the multidisciplinary scientific Petermann 2015 Expedition on the icebreaker Oden. During 239.4 hours of dedicated observation effort, a total of 312 individuals were recorded, representing four species: bearded seal (Erignathus barbatus), hooded seal (Crystophora cristata), harp seal (Pagophilus groenlandicus), and ringed seal (Pusa hispida). Ringed seals were recorded significantly more than the other species (\χ2 = 347.4, df = 3, p \< 0.001, n = 307). We found significant differences between species in haul-out (resting on ice) behavior (\χ2 = 133.1, df = 3, p \< 0.001, n = 307). Bearded seals were more frequently hauled out (73.1\% n = 49), whereas ringed seals were almost exclusively in water (93.9\%, n = 200). Differences in average depth and ice coverage where species occurred were also significant: harp seals and bearded seals were found in deeper water and areas of greater ice coverage (harp seals: 663 \± 366 m and 65 \± 14\% ice cover; bearded seals: 598 \± 259 m and 50 \± 21\% ice cover), while hooded seals and ringed seals were found in shallower water with lower ice coverage (hooded seals: 490 \± 163 m and 38 \± 19\% ice cover; ringed seals: 496 \± 235 m, and 21 \± 20\% ice cover). Our study provides an initial look at how High Arctic seals use the rapidly changing Petermann Fjord and how physical variables influence their distribution in one of the few remaining ice-tongue fjord environments.

}, keywords = {Petermann Glacier; marine mammals; ice-tongue fjord; Arctic seals; sea ice; Pusa hispida; Erignathus barbatus; Crystophora cristata; Pagophilus groenlandicus}, doi = {https://doi.org/10.14430/arctic4735}, url = {https://arctic.journalhosting.ucalgary.ca/arctic/index.php/arctic/article/view/4735}, author = {Lomac-MacNair, K. and Martin Jakobsson and Mix, A C and Freire, Francis F and Hogan, Kelly and Larry A Mayer and Smultea, Mari Ann} } @article {6330, title = {Submerged Sea Caves of Southern California{\textquoteright}s Continental Borderland}, volume = {31(1)}, year = {2018}, month = {March}, pages = {30-31}, url = {https://tos.org/oceanography/assets/docs/31-1_supplement.pdf}, author = {Robert Ballard and Nicole A Raineault and Jason Fahy and Larry A Mayer and Erin Heffron and Kenneth Broad and Julie Bursek and Chris Roman and Kristopher Krasnosky} } @article {6217, title = {Acoustic Mapping of Thermohaline Staircases in the Arctic Ocean}, volume = {7:15192}, year = {2017}, month = {November 9}, pages = {1-9}, publisher = {Springer Nature}, abstract = {

Although there is enough heat contained in inflowing warm Atlantic Ocean water to melt all Arctic sea ice within a few years, a cold halocline limits upward heat transport from the Atlantic water. The amount of heat that penetrates the halocline to reach the sea ice is not well known, but vertical heat transport through the halocline layer can significantly increase in the presence of double diffusive convection. Such convection can occur when salinity and temperature gradients share the same sign, often resulting in the formation of thermohaline staircases. Staircase structures in the Arctic Ocean have been previously identified and the associated double diffusive convection has been suggested to influence the Arctic Ocean in general and the fate of the Arctic sea ice cover in particular. A central challenge to understanding the role of double diffusive convection in vertical heat transport is one of observation. Here, we use broadband echo sounders to characterize Arctic thermohaline staircases at their full vertical and horizontal resolution over large spatial areas (100\ s of kms). In doing so, we offer new insight into the mechanism of thermohaline staircase evolution and scale, and hence fluxes, with implications for understanding ocean mixing processes and ocean-sea ice interactions.

}, doi = {10.1038/s41598-017-15486-3}, url = {https://www.nature.com/articles/s41598-017-15486-3}, author = {Christian Stranne and Larry A Mayer and Thomas C Weber and Ruddick, Barry R and Martin Jakobsson and Kevin Jerram and Elizabeth Weidner and Johan Nilsson and Katarina G{\r a}rdfeldt} } @article {6796, title = {Advancement in the Estimation of Gas Seep Flux from Echosounder Measurements}, year = {2017}, month = {March 20-23}, pages = {Galveston, TX}, author = {Elizabeth Weidner and Larry A Mayer and Thomas C Weber} } @article {6805, title = {Analysis of the Radiated Sound Field of Deep Water Multibeam Echo Sounders for Return Intensity Calibration Using an Underwater Hydrophone Array}, volume = {142(2)}, year = {2017}, month = {November 16}, pages = {2731-2731}, publisher = {Acoustical Society of America}, abstract = {

Multibeam echo sounders (MBES) are tools used to gather geophysical information on the seafloor and watercolumn which are important for feature detection, identifying gas seeps, and characterizing the seafloor, among others. At high frequencies (\>100 kHz), MBES can be calibrated for their ensonification patterns in test tanks. However, deep water MBES feature long transmit arrays and varying geometries that make tank calibration impractical. The transmit arrays can be over 8m and have a far field range in the hundreds of meters. In addition, these systems use beam steering techniques to segment the swath into multiple sectors to mitigate ship motions, which complicates the radiated pattern and return intensity. This study will better characterize the radiated sound field of deep water MBES for return intensity calibration. A MBES survey was conducted using a Kongsberg EM122 MBES on the SCORE range, a submerged broadband hydrophone array. Hydrophones were spaced ~5 km apart and were continuously recording during the survey. The EM112 is a multisector dual swath system operated at 12 kHz with CW waves. Hydrophone data were analyzed, and the resultant radiated sound field was determined at different distances and angles.

}, doi = {10.1121/1.5014973}, author = {Michael Smith and Thomas C Weber and Larry A Mayer and David Moretti and Anthony P. Lyons and Val Schmidt} } @article {6166, title = {BedMachine v3: Complete Bed Topography and Ocean Bathymetry Mapping of Greenland From Multibeam Echo Sounding Combined With Mass Conservation}, volume = {44}, year = {2017}, month = {November 1}, pages = {11}, publisher = {John Wiley and Sons, Inc.}, abstract = {

Greenland\&$\#$39;s bed topography is a primary control on ice flow, grounding line migration, calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic water (AW) that rapidly melts and undercuts Greenland\&$\#$39;s marine-terminating glaciers. Here we present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness data through a mass conservation approach. A new 150\ m horizontal resolution bed topography/bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface, yielding major improvements over previous data sets, particularly in the marine-terminating sectors of northwest and southeast Greenland. Our map reveals that the total sea level potential of the Greenland ice sheet is 7.42 \± 0.05 m, which is 7\ cm greater than previous estimates. Furthermore, it explains recent calving front response of numerous outlet glaciers and reveals new pathways by which AW can access glaciers with marine-based basins, thereby highlighting sectors of Greenland that are most vulnerable to future oceanic forcing.

}, doi = {10.1002/2017GL074954}, url = {http://onlinelibrary.wiley.com/doi/10.1002/2017GL074954/abstract;jsessionid=158B0362B92B2C2D0D7ECF2F8104691C.f02t02}, author = {Morlighem, M. and C.N. Williams and Rignot, E. and An, J. and Jan Erik Arndt and Bamber, J.L. and Catania, G. and Chauche, N. and Dowdeswell, J and Dorschel, B. and Fenty, I. and Hogan, K. and Howat, I. and Hubbard, A. and Martin Jakobsson and Thomas Jordan and Kjeldsen, K.K. and Millan, R. and Larry A Mayer and Mouginot, J. and Noel, B.P.Y. and O{\textquoteright}Cofaigh, C. and Palmer, S. and Rysgaard, S. and Seroussi, H. and Siegert, M and Slabon, P. and Straneo, F. and van den Broeke, M.R. and Weinrebe, W. and Wood, M. and Zinglersen, K.B.} } @article {6218, title = {Correlating Sea Level Rise Still-stands to Marine Terraces and Undiscovered Submerged Shoreline Features in the Channel Islands (USA) Using Autonomous and Remotely Operated Systems}, year = {2017}, month = {December 11-15}, pages = {New Orleans, LA}, abstract = {

In 2017, the Ocean Exploration Trust aggregated onboard and autonomous mapping technologies to identify and explore paleo shorelines and discover previously undocumented submerged shoreline features in and around the Channel Islands offshore of California. Broad area mapping was conducted with the hull mounted multibeam echosounder aboard the E/V Nautilus. This Kongsberg EM302 provided maps at 2-10 m resolution, at depths generally greater than 50 m. From this data marine terraces were identified for higher resolution mapping via an Autonomous Surface Vehicle (ASV). The precision data from the ASV\’s Kongsberg EM2040p echosounder allowed identification of the knickpoints associated with cliffs on the landward extent of each terrace. Sub-sea cave targets were identified using backscatter and slope maps from a combination of both the broad area and high resolution multibeam data. To ground-truth the targets identified through mapping, remotely operated vehicles (ROVs) and a highly specialized team of cave divers explored these targets. The results from the visual inspection were then fed back into the analysis fostering the rapid iteration of the onboard identification criteria and resulted in locating submerged shorelines containing numerous large caves, arches, and concretions. Caves were found at still-stands at 8, 33, 66, and 103 m depth at Santa Cruz Island, Santa Barbara Island platform, and Osborn Bank, along the vertical escarpment at the cliff-face and aligned with the strike of fractures in the volcanic rock. These terraces correspond to different sea level still-stands. ROV grab samples of fossiliferous marine terraces will provide ages and aid in reconstructions of sea level change and tectonic history for each location. Finally, caves were mapped in sub-cm resolution using a Kongsberg M3 sonar mounted vertically on the front of the ROV to test the capabilities of the system to provide accurate information about exterior dimensions and morphology.\ 

}, keywords = {asv, backscatter, bathymetry, em302, multibeam, ROV}, url = {https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/292497}, author = {Nicole A Raineault and Robert Ballard and Jason Fahy and Larry A Mayer and Erin Heffron and Kristopher Kranosky and Chris Roman and Val Schmidt and Andy McLeod and Julie Bursek and Kenneth Broad} } @article {6236, title = {The De Long Trough: A Newly Discovered Glacial Trough on the East Siberian Continental Margin}, volume = {13,9}, year = {2017}, month = {September 28}, pages = {1269-1284}, publisher = {Copernicus Publications}, abstract = {

Ice sheets extending over parts of the East Siberian continental shelf have been proposed for the last glacial period and during the larger Pleistocene glaciations. The sparse data available over this sector of the Arctic Ocean have left the timing, extent and even existence of these ice sheets largely unresolved. Here we present new geophysical mapping and sediment coring data from the East Siberian shelf and slope collected during the 2014 SWERUS-C3 expedition (SWERUS-C3: Swedish \– Russian \– US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions). The multibeam bathymetry and chirp sub-bottom profiles reveal a set of glacial landforms that include grounding zone formations along the outer continental shelf, seaward of which lies a \>65m thick sequence of glacio-genic debris flows. The glacial landforms are interpreted to lie at the seaward
end of a glacial trough \– the first to be reported on the East Siberian margin, here referred to as the De Long Trough because of its location due north of the De Long Islands. Stratigraphy and dating of sediment cores show that a drape of acoustically laminated sediments covering the glacial deposits is older than 50 cal kyr BP. This provides direct evidence for extensive glacial activity on the Siberian shelf that predates the Last Glacial Maximum and most likely occurred during the Saalian (Marine Isotope Stage (MIS) 6).

}, doi = {doi:10.5194/cp-2017-56, 2017}, url = {https://www.clim-past.net/13/1269/2017/cp-13-1269-2017.pdf}, author = {O{\textquoteright}Regan, M A and Backman, Jan and Barrientos, Natalia and Cronin, Tomas and Laura Gemery and Kirchner, N. and Larry A Mayer and Johan Nilsson and Noormets, R. and Pearce, Christof and Semiltov, I. and Christian Stranne and Martin Jakobsson} } @article {6244, title = {The Deglacial to Holocene Paleoceanography of Bering Strait: Results From the SWERUS-C3 Program}, year = {2017}, month = {December 11-15}, pages = {New Orleans, LA}, abstract = {

The climate-carbon-cryosphere (C3) interactions in the East Siberian Arctic Ocean and related ocean, river and land areas of the Arctic have been the focus for the SWERUS-C3 Program (Swedish \– Russian \– US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions). This multi-investigator, multi-disciplinary program was carried out on a two-leg 90-day long expedition in 2014 with Swedish icebreaker Oden. One component of the expedition consisted of geophysical mapping and coring of Herald Canyon, located on the Chukchi Sea shelf north of the Bering Strait in the western Arctic Ocean. Herald Canyon is strategically placed to capture the history of the Pacific-Arctic Ocean connection and related changes in Arctic Ocean paleoceanography. Here we present a summary of key results from analyses of the marine geophysical mapping data and cores collected from Herald Canyon on the shelf and slope that proved to be particularly well suited for paleoceanographic reconstruction. For example, we provide a new age constraint of 11 cal ka BP on sediments from the uppermost slope for the initial flooding of the Bering Land Bridge and reestablishment of the Pacific-Arctic Ocean connection following the last glaciation. This age corresponds to meltwater pulse 1b (MWP1b) known as a post-Younger Dryas warming in many sea level and paleoclimate records. In addition, high late Holocene sedimentation rates that range between about 100 and 300 cm kyr-1, in Herald Canyon permitted paleoceanographic reconstructions of ocean circulation and sea ice cover at centennial scales throughout the late Holocene. Evidence suggests varying influence from inflowing Pacific water into the western Arctic Ocean including some evidence for quasi-cyclic variability in several paleoceanographic parameters, e.g. micropaleontological assemblages, isotope geochemistry and sediment physical properties.

}, url = {https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/214305}, author = {Martin Jakobsson and Anderson, L and Backman, Jan and Barrientos, Natalia and Bjork, G and Helen K. Coxall and Cronin, Tomas and de Boer, A. and Laura Gemery and Kevin Jerram and Johansson, Carina and Kirchner, N. and Larry A Mayer and M{\"o}rth, C-M. and Johan Nilsson and Noormets, R. and O{\textquoteright}Regan, M A and Pearce, Christof and Semiltov, I. and Christian Stranne} } @article {6225, title = {Distribution of an Acoustic Scattering Layer, Petermann Fjord, Northwest Greenland}, year = {2017}, month = {December 11-15}, pages = {New Orleans, LA}, abstract = {

The Petermann 2015 Expedition was a comprehensive paleoceanographic and paleoclimatological study of the marine-terminating Petermann Glacier and its outlet system in Northwest Greenland carried out July-August 2015. The purpose was the reconstruction of glacial history and current glacial processes in Petermann Fjord to better understand the fate of the Petermann Glacier and its floating ice tongue that acts as a critical buttressing force to the outlet glacier draining about 4\% of the Greenland Ice Sheet. Seafloor mapping was a critical component of the study and an EM122 multibeam sonar was utilized for this purpose; additionally, water column data were acquired with this sonar and an EK80 split-beam echosounder.

During the expedition, the mapping team noted an acoustic scattering layer in the EK80 and EM122 water column data which was observed to change depth in a spatially consistent manner that appeared to be related to location. Initial onboard processing revealed what appears to be a strong spatial coherence in the layer distribution that corresponds to our understanding of the complex circulation pattern in the study area, including inflow of warmer Atlantic waters and outflow of subglacial waters. This initial processing was limited to observations at 46 discrete locations that corresponded to CTD stations, a very small subset of the 4800 line kilometers of data collected by each sonar. Both sonars were run 24 hours per day over the 30-day expedition, providing continuous time-varying acoustic coverage of the study area.

Post-cruise additional data has been processed to extract the acoustic returns from the scattering layer using a combination of commercial sonar processing software and specialized MATLAB and Python routines. 3-D surfaces have been generated from the extracted points in order to visualize the continuous spatial and temporal distribution of the scattering layer across the entire study area. Multiple crossings of the same location at different times of day address the question of the temporal stability of the scattering layer while the detailed map of the spatial distribution demonstrates the relationship of the scattering layer to the water masses and implies that continuous acoustic coverage may be a powerful proxy for oceanography.

}, keywords = {acoustic, arctic, DSL, EK80, EM122, Petermann, scattering layer}, url = {https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/287293}, author = {Erin Heffron and Larry A Mayer and Martin Jakobsson and Hogan, Kelly and Kevin Jerram} } @article {6097, title = {How to Improve the Quality and the Reproducibility for Acoustic Seafloor Characterization}, year = {2017}, month = {May 1-5}, pages = {Nova Scotia, Canada}, abstract = {

Current commercial solutions for processing acoustic data with the aim of seafloor characterization does not take full advantage of the wide spectra of information collected by modern sonars (e.g., water column data, multiple sectors). In addition, those solutions tend to act as a \‘magic black-box\’ with only a few user-defined parameters. This can be seen as an advantage (it makes these technologies available to a large community), but it also engenders a lack of data reproducibility. Currently, it is a real challenge to \‘properly\’ merge backscatter-based products from different vendors (and even from the same vendor given the lack of metadata).

In order to mitigate both issues, we developed a different approach. The proposed workflow is organized into two main phases: the first part focuses on artifact identification and reduction, while the second part is product-oriented. The artifact-oriented phase applies a (growing) set of algorithms to facilitate the identification of corrupted data so that they can then be ignored or, if required by the user, reconstructed using several different techniques. This approach also provides a metric that can then be used to identify which ping should be excluded during seafloor characterization.

The first phase is cleanly separated from the product creation. At the end of it, corrected data in the sonar\’s native format are generated together with an (optional) \‘difference\’ file (containing only the data that has been modified) and a human-readable and computer-interpretable textual description of all the applied processes. This \‘native-format\’ solution is better than converting the data to a hybrid generic data format which may not adequately preserve all of the important information from the file. The \‘difference\’ files reduce the amount of data storage since they contain only the changes, rather than doubling the storage requirement. An additional advantage is modularity. For instance, based on the kind of survey different strategies combining the identification and reduction methods can be built. Once the valid, corrected data files are created, they can be mosaicked or analyzed for seafloor characterization by the user-preferred application.

The proposed approach is demonstrated with real-world data by first using a set of bubble washdown detection algorithms, then improving the quality of the generated outputs. Specifically, the mosaic is created after the reconstruction of the corrupted samples with a weighted randomization schema, while the seafloor characterization is improved by ignoring the corrupted data.

A possible future development of this approach is to carry all the line-based descriptions of the applied processes together with the products. To make this possible in a robust way, we propose the creation of an open, community-driven product data format mimicking what has been done for bathymetric data by the Open Navigation Surface Working Group (BAG format).

}, keywords = {angular response curve, artifacts, backscatter, marianas, Seafloor Characterization}, doi = {10.4095/305398}, url = {http://geohab2017.wixsite.com/geohab2017/program}, author = {Giuseppe Masetti and Brian R Calder and Larry A Mayer} } @article {6246, title = {Implementation of an Acoustic-based Methane Flux Estimation Methodology in the Eastern Siberian Arctic Sea }, year = {2017}, month = {December 11-15}, pages = {New Orleans, LA}, abstract = {

Quantifying methane flux originating from marine seep systems in climatically sensitive regions is of critically importance for current and future climate studies. Yet, the methane contribution from these systems has been difficult to estimate given the broad spatial scale of the ocean and the heterogeneity of seep activity. One such region is the Eastern Siberian Arctic Sea (ESAS), where bubble release into the shallow water column (\<40 meters average depth) facilitates transport of methane to the atmosphere without oxidation. Quantifying the current seep methane flux from the ESAS is necessary to understand not only the total ocean methane budget, but also to provide baseline estimates against which future climate-induced changes can be measured.

At the 2016 AGU fall meeting, we presented a new acoustic-based flux methodology using a calibrated broadband split-beam echosounder. The broad (14-24 kHz) bandwidth provides a vertical resolution of 10 cm, making possible the identification of single bubbles. After calibration using 64 mm copper sphere of known backscatter, the acoustic backscatter of individual bubbles is measured and compared to analytical models to estimate bubble radius. Additionally, bubbles are precisely located and traced upwards through the water column to estimate rise velocity. The combination of radius and rise velocity allows for gas flux estimation.

Here, we follow up with the completed implementation of this methodology applied to the Herald Canyon region of the western ESAS. From the 68 recognized seeps, bubble radii and rise velocity were computed for more than 550 individual bubbles. The range of bubble radii, 1-6 mm, is comparable to those published by other investigators, while the radius dependent rise velocities are consistent with published models. Methane flux for the Herald Canyon region was estimated by extrapolation from individual seep flux values.

}, url = {https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/228715}, author = {Elizabeth Weidner and Thomas C Weber and Larry A Mayer} } @article {6795, title = {Investigating Bubble Transport and Fate in the Watercolumn with Calibrated Broadband Split-Beam Echosounder Data}, year = {2017}, month = {December 4-8}, pages = {New Orleans, LA}, author = {Elizabeth Weidner and Thomas C Weber and Larry A Mayer} } @article {6247, title = {A Multi-Frequency Investigation of the Influences of Groundwater Discharge on Hydrocarbon Emission and Transport in the Baltic Sea}, year = {2017}, month = {December 11-15}, pages = {New Orleans, LA}, abstract = {

In nearshore coastal regions submarine groundwater discharge is a major component of the hydro-geological cycle: transporting nutrients and pollutants to the ocean, producing up-welling currents through buoyancy effects, and acting as an erosional force at discharge sites. In nearshore regions where biogenic gas production is high, groundwater discharge could potentially act as a control on hydrocarbon emission and transport from the seafloor though the water-column.

In the southern Stockholm Archipelago of the Baltic Sea, terraces and semi-circular depressions on shallow (\<20 meters) seafloor have been linked to the discharge of ground water, traveling along the permeable layers in glacial clay deposits (S\öderberg and Flod\én 1995; Jakobsson et al., 2016). Sub-bottom profiles over the same region have identified widespread areas of subsurface blanking, commonly attributed to gas, as well as water-column seep features, both in spatial proximity to the groundwater discharge sites.

High-resolution multibeam bathymetry and chirp sub-bottom profiles were combined with water-column data sets collected at multiple frequencies (300 kHz, 45-90 kHz, 160-260 kHz) to map the spatial distribution of seeps and investigate their relationship to localized groundwater discharge as determined by seafloor and subsurface morphology. The spatial extent of seep sites appears closely tied to regions of suspected groundwater discharge, suggesting direct or indirect controls on gas emission pathways. Additionally, seep morphology in the broadband data hints at the possibility of groundwater and gas flow mixing.

}, url = {https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/230878}, author = {Elizabeth Weidner and Martin Jakobsson and Nycander, J and Larry A Mayer} } @article {6237, title = {Post-Glacial Flooding of the Bering Land Bridge Dated to 11 cal ka BP Based on New Geophysical and Sediment records}, volume = {13}, year = {2017}, month = {August 1}, pages = {991-1005}, publisher = {Copernicus Publications}, abstract = {

The Bering Strait connects the Arctic and Pacific oceans and separates the North American and Asian landmasses. The presently shallow ( 53 m) strait was exposed during the sea level lowstand of the last glacial period, which permitted human migration across a land bridge today referred to as the Bering Land Bridge. Proxy studies (stable isotope composition of foraminifera, whale migration into the Arctic Ocean, mollusc and insect fossils and paleobotanical data) have suggested a range of ages for the Bering Strait reopening, mainly falling within the Younger Dryas stadial (12.9\–11.7 cal ka BP). Here we provide new information on the deglacial and post-glacial evolution of the Arctic\–Pacific connection through the Bering Strait based on analyses of geological and geophysical data from Herald Canyon, located north of the Bering Strait on the Chukchi Sea shelf region in the western Arctic Ocean. Our results suggest an initial opening at about 11 cal ka BP in the earliest Holocene, which is later than in several previous studies. Our key evidence is based on a well-dated core from Herald Canyon, in which a shift from a near-shore environment to a Pacific-influenced open marine setting at around 11 cal ka BP is observed. The shift corresponds to meltwater pulse 1b (MWP1b) and is interpreted to signify relatively rapid breaching of the Bering Strait and the submergence of the large Bering Land Bridge. Although the precise rates of sea level rise cannot be quantified, our new results suggest that the late deglacial sea level rise was rapid and occurred after the end of the Younger Dryas stadial.

}, doi = {doi.org/10.5194/cp-13-991-2017}, url = {https://www.clim-past.net/13/991/2017/cp-13-991-2017.pdf}, author = {Martin Jakobsson and Pearce, Christof and Cronin, Tomas and Backman, Jan and Anderson, Louise and Barrientos, Natalia and Bjork, G and Helen K. Coxall and de Boer, A. and Larry A Mayer and M{\"o}rth, C-M. and Johan Nilsson and Rattray, J.E. and Christian Stranne and Semiltov, I. and O{\textquoteright}Regan, M A} } @article {6245, title = {Seafloor Mapping: We{\textquoteright}ve Come a Long Way {\textendash} But Still Have Far to Go}, year = {2017}, month = {December 11-15}, pages = {New Orleans, LA}, abstract = {

Our ability to map the seafloor has changed radically over the past century. For thousands of years a weight at the end of a rope (or wire) \– a lead line -- provided the only means to measure depth. By the end of the Second World War, single beam echo sounders had been perfected to the extent that they became common on oceanographic and other vessels providing more rapid but laterally averaged (typically over a distance commensurate with the water depth) measurements of seafloor depths. Towards the end of the 20th Century \– two great advances were made in seafloor mapping \– the development of techniques to use satellite altimetry to predict seafloor bathymetry and the evolution of multibeam sonar technology from classified military applications to the academic and commercial communities. Satellite-altimetry derived bathymetry provides an unprecedented view of seafloor topography and tremendous insight into tectonic-scale processes but is limited in achievable resolution. Multibeam sonars offer the potential of extremely high-resolution (a function of array size, beam footprint, and water depth), but are typically deployed from manned surface vessels that cover limited amount of seafloor at a relatively high daily cost. We have the technology to map the entire world ocean with multibeam sonar but It has been estimated that to map the world ocean deeper than about 150m (shallow water is very time-consuming and expensive because the coverage swath width is typically 3-5 times water) would take approximately 200 ship years and cost on the order of 3 billion dollars. We have demonstrated our willingness to spend billions to map other planets (e.g. Mars and the Moon) but for some reason, not our own. Recently, however, there has been growing momentum to see the entire world ocean mapped. The Nippon Foundation and GEBCO have recently announced the Seabed 2030 project with a goal of facilitating the mapping of the world ocean by 2030 and international agreements like The Galway Statement on Atlantic Cooperation are coordinating international efforts to see large portions of the seafloor mapped. Coupled with these international efforts, new technologies like autonomous mapping barges or large-scale multibeam sonar equipped Saildrones may greatly reduce costs and make the dream of mapping the world ocean at high-resolution a reality.

}, url = {https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/216626}, author = {Larry A Mayer} } @article {5798, title = {Acoustic and Geomorphological Signatures of Gas Seeps on the East Siberian Margin}, year = {2016}, month = {April 11-12}, address = {University of New Hampshire, Durham, NH}, abstract = {

Rising hydrocarbon gas concentrations in the atmosphere are strongly linked to global warming. In the next century, significant amounts of hydrocarbons will be transport from the ocean to the atmosphere via thawing of flooded permafrost. The East Siberian Arctic Shelf (ESAS) holds 80\% of the world\’s flooded permafrost and is at risk of massive release due to bottom water warming. Gas released from permafrost is transported by gas seeps through the ocean; however, the magnitude of this gas flux has historically been difficult to quantify.

This research aims to estimate the total gas flux from a region of the ESAS, Herald Canyon, via acoustic and geomorphological characterization of gas seeps in the area. Data was collected with three acoustic systems (EM122 multibeam echosounder, SBP120 subbottom profiler, and EK80 split-beam sonar) onboard the Oden during the Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions (SWERUS-C3) program.

53 seeps have been identified in the vicinity of Herald Canyon. Together, the EM122 high-resolution multibeam bathymetry and SBP120 chirp subbottom profiling data, provide the spatial and geologic context of the gas seeps. The EK80, which makes acoustic measurements over a broad range of frequencies, can identify individual bubble scatters. This enables estimates of bubble size distribution and rise velocity measurements in certain seeps; ultimately providing gas flux estimates. The combination of three data sets offers the opportunity to link seep flux estimates to geomorphological setting. The geomorphological setting can further be linked to local and regional geologic processes determined from seafloor morphology and subsurface structure. These links will help define our knowledge of the transport of hydrocarbon gas from flooded permafrost to the atmosphere.

}, keywords = {acoustic, east siberian margin, gas seeps, geomorphological signatures}, author = {Elizabeth Weidner and Larry A Mayer and Kevin Jerram and Thomas C Weber and Martin Jakobsson and Chernykh, D. and Ananiev, R. and Mohammad, R. and Semiltov, I.} } @inbook {5813, title = {The Arctic Continental Shelf and Its Evolving Morphologic Context}, booktitle = {Challenges of the Changing Arctic: Continental Shelf, Navigation and Fisheries}, volume = {19}, year = {2016}, pages = {17{\textendash}41}, publisher = {Brill Nijhoff Press}, organization = {Brill Nijhoff Press}, chapter = {3}, address = {Leiden, The Netherlands}, keywords = {arctic, continental shelf, morphology}, doi = {10.1163/9789004314252_005 }, author = {Larry A Mayer}, editor = {Nordquist, M. and Moore, J M and Ron{\'a}n Long} } @inbook {5392, title = {Cascades and Plunge Pools in the Gulf of Alaska}, booktitle = {Atlas of Submarine Glacial Landforms: Modern, Quaternary and Ancient}, volume = {Memoirs}, number = {46}, year = {2016}, month = {12/2016}, pages = {389-390}, publisher = {Geological Society of London }, organization = {Geological Society of London }, address = {London, UK}, abstract = {

In the summer of 2005, the University of New Hampshire\’s Center for Coastal and Ocean Mapping/Joint Hydrographic Center, mapped more than 321,400 sq. km. of seafloor in the Gulf of Alaska in support of efforts to establish the limits of the juridical continental shelf of the United States as defined under the Law of the Sea Treaty. Both bathymetry and high-resolution backscatter data were collected with a 12-kHz EM120 multibeam echoshounder aboard the University of Hawaii\’s R/V Kilo Moana. The resulting digital terrain models and backscatter mosaics (presented as average backscatter normalized to 45o) provide a remarkable view of the processes on a tectonically active, glaciated margin including the formation of numerous submarine channels (Gardner and Mayer, this volume) and large deep submarine fans (Gardner and Mayer, this volume). In the course of these surveys, several morphological features similar to cascades and plunge pools that are found beneath terrestrial waterfalls were identified on the continental slope.

}, keywords = {cascades, gulf of alaska, plunge pools}, doi = {doi:10.1144/M46.20}, author = {Larry A Mayer and James V. Gardner} } @inbook {5393, title = {Chatham Fan and Adjacent Upper Baranof Fan Channels and Levee, U.S. Gulf of Alaska Margin}, booktitle = {Atlas of Submarine Glacial Landforms: Modern, Quaternary and Ancient}, volume = {Memoirs}, number = {46}, year = {2016}, month = {12/2016}, pages = {387}, publisher = {Geological Society of London }, organization = {Geological Society of London }, address = {London, UK}, abstract = {

The University of New Hampshire\’s Center for Coastal \& Ocean Mapping collected ~321,500 km2 of bathymetry and backscatter data of the U.S. Gulf of Alaska continental margin (Fig. 1a) using a 12-kHz multibeam echosounder in support of the U.S. Extended Continental Shelf (United Nations Law of the Sea Treaty) project (Gardner and Mayer, 2005). A previously unmapped small submarine fan, unofficially named Chatham fan (Figs. 1b and 1c), was identified that has buried a portion of the head of the much larger Baranof Fan (Stevenson and Embley, 1987; von Huene, 1989; LeVoir et al., 2011). Chatham fan either buried or diverted to the NW the upper reaches of Horizon Channel. The existing levee of upper Horizon Channel was subsequently incised by a remarkable meandering channel that trends along the strike of the levee, not down the steeper lee side of the levee slope. Although not directly related to Chatham fan, the meandering levee channel is related to processes that were contemporaneous with the deposition of Chatham fan. \ 

}, doi = { https://doi.org/10.1144/M46.18}, author = {James V. Gardner and Larry A Mayer} } @article {5814, title = {Evidence for an Ice Shelf Covering the Central Arctic Ocean During the Penultimate Glaciation}, volume = {7}, year = {2016}, month = {January 18}, publisher = {Macmillan Publishers Ltd.}, abstract = {

The hypothesis of a km-thick ice shelf covering the entire Arctic Ocean during peak glacial conditions was proposed nearly half a century ago. Floating ice shelves preserve few direct traces after their disappearance, making reconstructions difficult. Seafloor imprints of ice shelves should, however, exist where ice grounded along their flow paths. Here we present new evidence of ice-shelf groundings on bathymetric highs in the central Arctic Ocean, resurrecting the concept of an ice shelf extending over the entire central Arctic Ocean during at least one previous ice age. New and previously mapped glacial landforms together reveal flow of a spatially coherent, in some regions \>1-km thick, central Arctic Ocean ice shelf dated to marine isotope stage 6 (~140\ ka). Bathymetric highs were likely critical in the ice-shelf development by acting as pinning points where stabilizing ice rises formed, thereby providing sufficient back stress to allow ice shelf thickening.

}, keywords = {Arctic Ocean, glaciation, ice shelf}, doi = {doi:10.1038/ncomms10365}, url = {http://www.nature.com/ncomms/2016/160118/ncomms10365/full/ncomms10365.html}, author = {Martin Jakobsson and Johan Nilsson and Anderson, L and Backman, Jan and Bjork, G and Cronin, Tomas and Kirchner, N. and Koshurnikov, Andrey and Larry A Mayer and Noormets, R. and O{\textquoteright}Regan, M A and Christian Stranne and Ananiev, R. and Barrientos, Natalia and Chernykh, D. and Helen K. Coxall and Bjorn Eriksson and Floden, Tom and Laura Gemery and Gustafson, Orjan and Kevin Jerram and Johansson, Carina and Khortov, Alexey and Mohammad, R. and Semiltov, I.} } @article {5815, title = {Exploration of Hydrothermal Vents Along the Galapagos Spreading Center}, volume = {29, No.1, Supplement}, year = {2016}, month = {March}, pages = {35-7}, publisher = {The Oceanography Society}, keywords = {galapagos, hydrothermal vents}, url = {http://tos.org/oceanography/assets/images/content/29-1_supplement.pdf}, author = {Nicole A Raineault and Robert Ballard and Larry A Mayer and Fisher, Charles R. and Carey, S. and Marsh, Leigh and Renato Kane and T{\"u}z{\"u}n, Suna and Shank, T M and Smart, Clara} } @article {6003, title = {The Glacimarine Sediment Budget of the Nares Strait-Petermann Fjord Area Since the Last Glacial Maximum}, year = {2016}, month = {December 12-16}, address = {San Francisco, CA}, abstract = {

During the Petermann 2015 Expedition of the Swedish icebreaker Oden more than 6500 line-km of high-resolution chirp sub-bottom profiles (2-7 kHz) were acquired in Petermann Fjord and Nares Strait in the area immediately outside of the fjord. The sub-bottom profiles reveal a highly-variable distribution of post-glacial sediment that appears to be largely controlled by the rugged relief of the underlying bedrock. Sediment thicknesses are between 0-60 m above bedrock and comprise predominantly acoustically-stratified, homogeneous to transparent acoustic facies. In Petermann Fjord itself unlithified sediment cover typically comprises two units: an underlying acoustically-transparent unit overlain by an acoustically-stratified unit. Both of these units are conformable over scoured and fairly flat bedrock terrain; small basins are present only locally. Outside of the fjord are a few local sedimentary basins containing up to 40 m of stratified basin-fill deposits, and several areas of stacked mass-flow deposits. Glacial lineations both in the fjord and Nares Strait are formed in an acoustically-homogenous unit that underlies stratified and transparent units. In addition to the sub-bottom profiles, approximately 780 line-km of 2D seismic reflection profiles were acquired using an airgun (210 cu in.) and a 300-m long streamer. These profiles have allowed us to map full unlithified sediment thicknesses down to basement in the area. Here we present the results of this mapping and we calculate the volumes of a prominent grounding-zone wedge at the mouth of Petermann Fjord, and smaller GZWs in Kennedy Channel. These features demarcate former still-stand positions of grounded ice retreating through this system, both towards the present-day grounding line of Petermann Glacier and southwards through Nares Strait. Post-glacial sediment volumes are also calculated and the sedimentary processes responsible for their distribution examined. These data, when combined with chronological information, will provide sediment fluxes through the Petermann system and help us to identify how the system has responded to a past global warming event, namely the last deglaciation. This is particularly important in light of the recent thinning and acceleration of NW Greenland\’s marine-terminating outlet glaciers at present.

}, keywords = {glacial maximum, glacimarine sediment budget, nares strait, petermann fjord}, url = {https://agu.confex.com/agu/fm16/meetingapp.cgi/Paper/172466}, author = {Hogan, K. and Martin Jakobsson and Larry A Mayer and Mix, A C and Kevin Jerram and Nielsen, T. and Kamla, E. and Christian Stranne and Bjorn Eriksson} } @article {6002, title = {The History of Retreat Dynamics of Petermann Glacier Inferred from Submarine Glacial Landforms}, year = {2016}, month = {December 12-16}, pages = {San Francisco, CA}, abstract = {

Preserved submarine glacial landforms produced at the base and margin of ice sheets and outlet glaciers comprise records of past ice dynamics complementary to modern glaciological process studies. The Petermann 2015 Expedition on the Swedish icebreaker Oden systematically mapped approximately 3100 km2 of the seafloor in Petermann Fjord and the adjacent Hall Basin of Nares Strait, northwest Greenland, with an EM122 (12 kHz) multibeam and SBP120 (2-7 kHz) chirp sub-bottom profiler. Complete, overlapping mapping coverage permitted compilation of a high-quality (15x15m) digital terrain model (DTM). In addition, the seafloor at the margin of one of the smaller outlet glaciers draining into the Petermann Fjord and selected shallow areas along the coast were mapped using a small survey boat (RV Skidbladner), equipped with an EM2040 (200-300 kHz) multibeam. High-resolution (2 x 2 m) DTMs were compiled from the RV Skidbladner surveys. The seafloor morphology of Petermann Fjord and adjacent Hall Basin is dominated by a stunning glacial landform record comprising the imprints of Petermann Glacier\’s retreat dynamics since the Last Glacial Maximum (LGM). The entrance to Petermann Fjord consists of a prominent bathymetric sill formed by a large well-develop grounding zone wedge that undoubtedly represents a stability point during the glacier\’s retreat history. The deepest entrance to the fjord is 443 m and located on the southern side of this grounding zone wedge. Outside of this grounding zone wedge in Hall Basin, less well developed grounding zones appears to be present. The landform assemblage in between the grounding zones, in particular the lack of retreat ridges, may signify a leap-frog behavior of the glacier\’s retreat; rapid break-up and disintegration of the outlet glacier causing retreat back to the next stability point dictated by the local bedrock geology. While numerous classical glacial landforms characteristic for fast flowing ice streams are identified, the multibeam bathymetry also reveals an enigmatic, toilet bowl-shaped features whose origin is still unclear. The collected data during the Petermann 2015 Expedition will among other things provide new insights into ice shelf-ocean interactions, essential to projecting future climate impacts on Greenland and global sea level changes.

}, keywords = {petermann glacier, retreat dynamics, submarine glacial landforms}, url = {https://agu.confex.com/agu/fm16/meetingapp.cgi/Paper/164992}, author = {Martin Jakobsson and Hogan, K. and Larry A Mayer and Mix, A C and Kevin Jerram and Mohammad, R. and Christian Stranne and Bjorn Eriksson} } @inbook {6238, title = {Mapping Submarine Glacial Landforms Using Acoustic Methods}, booktitle = {Atlas of Submarine Glacial Landforms: Modern, Quaternary and Ancient}, volume = {Memoirs}, number = {46}, year = {2016}, month = {12/2016}, pages = {17-40}, publisher = {Geological Society of London}, organization = {Geological Society of London}, address = {London, UK}, doi = {doi:10.1144/M46.182}, author = {Martin Jakobsson and Gyllencreutz, R. and Larry A Mayer and Dowdeswell, J and Canals, M. and Todd, B J and Dowdeswell, E.K. and Hogan, Kelly and Larter, R.D.} } @article {5816, title = {Mapping the Eastern Pacific Ocean}, volume = {29, No.1, Supplement}, year = {2016}, month = {March}, pages = {38-9}, publisher = {The Oceanography Society}, abstract = {

E/V Nautilus conducts multibeam mapping surveys to create accurate bathymetric maps for science and for remotely operated vehicle (ROV) navigation. In addition, the ship collects bathymetric data during transits between ROV dive locations in previously unmapped areas that may lead to opportunities for future exploration. Between 2013 and 2015, Nautilus mapped over 211,355 km2 of seafloor in the Mediterranean, Atlantic, Caribbean, Gulf of Mexico, and eastern Pacific regions. Nearly 87,000 km2 were collected in 2015, due in large part to two long-distance transits from Galveston, TX, to the Gal\ápagos, and from the Gal\ápagos to San Diego, CA.

}, keywords = {eastern pacific, ocean mapping}, url = {http://tos.org/oceanography/assets/images/content/29-1_supplement.pdf}, author = {Nicole A Raineault and Larry A Mayer and Robert Ballard and Onni Irish} } @article {6000, title = {The Petermann Glacier Experiment, NW Greenland}, year = {2016}, month = {December 12-16}, pages = {San Francisco, CA}, abstract = {

The Petermann Glacier Experiment is a comprehensive study on land, ocean, and ice in Northwest Greenland, staged from Swedish Icebreaker Oden in 2015 as a collaboration between the US, Sweden, UK, and Denmark. This talk introduces the strategic goals of the experiment and connects the various scientific results. Petermann Glacier drains a significant marine-based sector of the northern Greenland Ice Sheet and terminates in a floating ice tongue, one of the largest remaining systems of its kind in the northern hemisphere. Records of the modern state of Petermann Glacier and its past variations are of interest to understand the sensitivity of marine terminating outlet glaciers to change, and to constrain the rates and extent of changes that have actually occurred. With this case study we are learning the rules of large scale dynamics that cannot be understood from modern observations alone. Although past behavior is not an simple analog for the future, and no single system captures all possible behaviors, insights from these case studies can be applied through models to better project how similar systems may change in the future. The Petermann Expedition developed the first comprehensive bathymetric maps of the region, drilled through the floating ice tongue to obtain sub-shelf sediment cores near the grounding line and to monitor sub-ice conditions, recovered a broad array of sediment cores documenting changing oceanic conditions in Petermann Fjord, Hall Basin, and Nares Strait, measured watercolumn properties to trace subsurface watermasses that bring heat from the Arctic Ocean into deep Petermann Fjord to melt the base of the floating ice tongue, developed a detailed record of relative sealevel change on land to constrain past ice loads, and recovered pristine boulders for cosmogenic exposure dating of areal ice retreat on land. Together, these studies are shedding new light on the dynamics of past glaciation in Northwest Greenland, and contributing to fundamental understanding of large marine-terminating outlet glacier systems, which are threatened by global warming and poised to contribute to global sealevel rise in the future. Further information in the Petermann Glacier Experiment is available at https://petermannsglacialhistory.wordpress.com

}, keywords = {greenland, petermann glacier}, url = {https://agu.confex.com/agu/fm16/meetingapp.cgi/Paper/139793}, author = {Mix, A C and Martin Jakobsson and Andrews, J.T. and Jennings, A. and Larry A Mayer and Anderson, S.T. and Brook, E. and Ceperley, E. and Cheseby, M. and John E. Hughes Clarke and Dalerum, F. and Dyke, L.M. and Einarsson, D. and Erkisson, D.B. and Frojd, C. and Glueder, A. and Hedman, U. and Heirman, K. and Heuze, C. and Hogan, K. and Padman, J. and Pecnerova, P. and Reilly, B. and Reusche, M. and Ross, A. and Christian Stranne and Marcott, S.A. and Muenchow, A. and Stoner, J S and Andresen, C.S. and Nicholls, K.W. and Holm, C. and Kevin Jerram and Krutzfeld, J. and Nicolas, L. and Par, L. and Lomac-MacNair, K. and Madlener, S. and McKay, J. and Meijer, T. and Meiton, A. and Brian, M. and Mohammad, R. and Molin, M. and Moser, C. and Normark, E. and Trinhammer, P. and Walczak, M.H. and Walczak, P. and Washam, P. and Karasti, M. and Anker, P.} } @article {5999, title = {Quantification of Methane Gas Flux and Bubble Fate on the Eastern Siberian Arctic Shelf Utilizing Calibrated Split-beam Echosounder Data}, year = {2016}, month = {December 12-16}, pages = {San Francisco, CA}, abstract = {

On the Eastern Siberian Arctic Shelf (ESAS) subsea permafrost, shallow gas hydrates, and trapped free gas hold an estimated 1400 Gt of methane. Recent observations of methane bubble plumes and high concentrations of dissolved methane in the water column indicate methane release via ebullition. Methane gas released from the shallow ESAS (\<50 m average depth) has high potential to be transported to the atmosphere.

To directly and quantitatively address the magnitude of methane flux and the fate of rising bubbles in the ESAS, methane seeps were mapped with a broadband split-beam echosounder as part of the Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions program (SWERUS-C3). Acoustic measurements were made over a broad range of frequencies (16 to 29 kHz). The broad bandwidth provided excellent discrimination of individual targets in the water column, allowing for the identification of single bubbles. Absolute bubble target strength values were determined by compensating apparent target strength measurements for beam pattern effects via standard calibration techniques. The bubble size distribution of seeps with individual bubble signatures was determined by exploiting bubble target strength models over the broad range of frequencies. For denser seeps, with potential higher methane flux, bubble size distribution was determined via extrapolation from seeps in similar geomorphological settings. By coupling bubble size distributions with rise velocity measurements, which are made possible by split-beam target tracking, methane gas flux can be estimated.

Of the 56 identified seeps in the SWERUS data set, individual bubbles scatterers were identified in more than half (31) of the seeps. Preliminary bubble size distribution results indicate bubble radii range from 0.75 to 3.0 mm, with relatively constant bubble size distribution throughout the water column. Initial rise velocity observations indicate bubble rise velocity increases with decreasing depth, seemingly independent of bubble radius.

}, keywords = {flux and bubble fate, methane gas, siberian arctic}, url = {https://agu.confex.com/agu/fm16/meetingapp.cgi/Paper/122698}, author = {Elizabeth Weidner and Larry A Mayer and Martin Jakobsson and Chernykh, D. and Ananiev, R. and Thomas C Weber and Kevin Jerram and Mohammad, R. and Semiltov, I.} } @article {5998, title = {Signs of Recent Volcanism and Hydrothermal Activity Along the Eastern Segment of the Galapagos Spreading Center}, year = {2016}, month = {December 12-16}, pages = {San Francisco, CA}, publisher = {American Geophysical Union }, address = {San Francisco, CA}, abstract = {

Since the initial discovery of the Gal\ápagos Spreading Center (GSC) vents in 1977, large-scale disturbances resulting from eruptive and tectonic activity have both destroyed and created vent habitats along the GSC. In 2015, the E/V Nautilus returned to the GSC with remotely operated vehicles (ROVs) to explore 17 kilometers of the rift valley from the Rosebud site in the west, to a previously unexplored temperature anomaly east of the Tempus Fugit vent site. In the years to over a decade since scientists last visited the Rosebud, Rose Garden, and Tempus Fugit sites, there were many changes. Most notably, the Rosebud site, where scientists found a nascent vent community and left site markers in 2002, was apparently covered with glassy basaltic sheet flows. In addition to visual exploration, oceanographic sensor measurements and direct sampling, we used the ROV Hercules imaging suite, comprised of stereo cameras and a structured light laser sensor to map an area of diffuse flow in the Tempus Fugit field (100 m x 150 m). The centimeter-level photographic and bathymetric maps created with this system, along with ROV HD video, samples, and environmental sensors, documented hydrothermal activity and changes in biological community structure (e.g., Riftia tubeworms observed in nascent stages of community development in 2011 were now, in 2015, in greater abundance (with tubes almost 4 m in length). The detection of active venting and associated faunal assemblages will provide insight into the temporal and spatial variability of venting activity at the Tempus Fugit site. On a visual survey of the Rift east of the Tempus Fugit site, extinct sulfide chimney structures were discovered and sampled. There were several chimneys and sulfide deposits in a span of over 8 km that ranged in height from over a half meter to 1.5 m tall. Diffuse flow hosting white and blue bacterial mats was observed near the chimneys complexes. The base of a large chimney structure, venting white fluids, as well as adjacent chemically-stained sediments supported vent-endemic fauna including the Pompeii worm (Alvinella pompejana) and other polychaete worms, along with pycnogonids, rat-tail fish, and galatheid crabs. This discovery provided the first evidence that the eastern segment of the GSC may have contained high-temperature, black smoker vents.\ 

}, keywords = {galpagos, hydrothermal activity, volcanism}, author = {Nicole A Raineault and Smart, Clara and Larry A Mayer and Robert Ballard and Fisher, Charles R. and Marsh, Leigh and Shank, T M} } @article {6001, title = {Towards the Complete Characterization of Marine-Terminating Glacier Outlet Systems}, year = {2016}, month = {December 12-16}, pages = {San Francisco, CA}, abstract = {

The Petermann Glacier Experiment was aimed at understanding past variations in Petermann Glacier and their relationship to changes in climatic and oceanographic conditions. A critical component of the experiment was a comprehensive program conducted on the icebreaker Oden to map submarine glacial landforms, offering insight into past ice dynamics and establishing the overall geomorphological context of the region. Concurrent water-column mapping provided remarkable insight into modern glacial, oceanographic, and biological processes suggesting that a carefully designed experiment could provide a near-complete characterization of marine-terminating glacier outlet systems.

Water-column mapping revealed seeps emanating from several seafloor regions. These features appeared along common depth zones and may represent fresh water emanating from a submerged aquifer; initial pore water analyses of cores also imply a fresh water flux into the fjord system. Water-column data also show a spatially consistent but variable distribution of a strong mid-water scattering layer, a biological response possibly tracing the inflow of Atlantic water into the fjord and enhanced by input from local outlet glaciers. The continuous nature of these acoustic records over 30 days offers a complete 4-D picture of the distribution of the scattering layer (and perhaps internal circulation patterns and water-mass interactions) with a spatial and temporal distribution far beyond that achievable by traditional oceanographic stations. Additional, higher-resolution water-column imaging around local outlet glaciers presents a clear picture of subglacial sediment-laden meltwater plumes. Thus in addition to the paleoceanographic information they provided, the acoustic systems deployed captured a 4D-view of many of the modern geological, oceanographic and ecological processes within and adjacent to the Petermann Glacier marine system. With the addition of seafloor and water-column sampling, long-term oceanographic moorings, a much more robust biological program (to understand what we are mapping in the water-column) and, the ability to extend our measurements under the ice sheet, we stand poised to truly characterize and hopefully understand the processes at work in front of marine-terminating outlet glaciers.

}, keywords = {marine-terminating glacier outlet systems, petermann glacier}, url = {https://agu.confex.com/agu/fm16/meetingapp.cgi/Paper/174118}, author = {Larry A Mayer and Martin Jakobsson and Mix, A C and Erin Heffron and Kevin Jerram and Hogan, K. and Muenchow, A.} } @inbook {5391, title = {An Ultrahigh-Latitude Submarine Channel: Northern Chukchi Rise}, booktitle = {Atlas of Submarine Glacial Landforms: Modern, Quaternary and Ancient.}, volume = {Memoirs}, number = {46}, year = {2016}, month = {12/2016}, pages = {391-392}, publisher = {The Geological Society of London}, organization = {The Geological Society of London}, address = {London, UK}, abstract = {

In support of efforts to establish an extended continental shelf under the auspices of the Law of the Sea Treaty, the United States and other nations have been collecting high-resolution multibeam sonar data in many previously unmapped regions of the Arctic. The U.S. has conducted eight dedicated mapping cruises since 2003 (four in collaboration with Canada) in the mostly ice-covered waters north of Alaska as far north as 83.5o N (Mayer et al., 2010) using the USCG Icebreaker HEALY equipped with a 12-kHz multibeam sonar. Given the generally heavy ice conditions in this region (the ice-edge was typically encountered at about 75o N), most of the surveys involved single multibeam swaths that cover specific targets relevant to a Law of the Sea submission (e.g., the 2500-m isobath or the foot of the slope). During the 2012 record-setting ice minimum, however, we found the ice margin at about 80oN that left large areas of open water available for mapping using more traditional overlapping multibeam survey techniques (Mayer and Armstrong, 2012). The complete coverage surveys carried out during 2012 revealed a remarkable, previously unknown submarine channel (informally named \“Weather Channel\”), most likely, the northern-most submarine channel ever mapped.

}, keywords = {chukchi, submarine channel}, doi = {doi:10.1144/M46.19}, author = {Larry A Mayer and James V. Gardner and Andrew A. Armstrong} } @article {5928, title = {U.S. Law of the Sea Cruise to Map and Sample the US Arctic Ocean Margin, Healy 1603}, year = {2016}, month = {October 6}, pages = {135}, institution = {Center for Coastal and Ocean Mapping / Joint Hydrographic Center}, address = {University of New Hampshire, Durham, NH}, abstract = {

Healy-1603 was a relatively short cruise that was scheduled late in the year when Healy time became available due to cancellation of a BOEM cruise. Originally scheduled for 11 days, the primary objective of was to collect a few key high-resolution multibeam sonar lines in the region north of the Alaskan north slope margin and on the Beringian margin to verify and further support initial foot of the slope (FoS) picks. With the decision to use Healy for ECS operations this season, discussions also began with the Canadians with respect to a possible two-ship operation with the Louis S. St. Laurent (LSL) which was scheduled for a seismic and mapping mission in the vicinity of the North Pole and the Alpha Ridge during August and September. Logistical constraints prevented the scheduling the ships for joint operations, however, both Canada and the U.S. agreed to extend their respective cruises by five days to accommodate high-priority objectives for each other -- the LSSL would attempt to collect a seismic line on the northern extension of Chukchi Cap for the U.S. and the Healy would attempt to dredge on the southern Alpha Ridge for Canada. Thus Healy-1603 was extended five days with the added objective of dredging on the Alpha Ridge. Ancillary projects on Healy-1603 included the deployment of ice buoys under the direction of Ignatius Rigor (University of Washington) and Pablo Clemente-Col\ón (NIC) (APPENDIX G) and the real-time underway isotopic analyses of seawater samples for ocean acidification studies under the direction of Jonathan Wynn from the University of Southern Florida (APPENDIX H). NIC on board personnel also provided sea ice analysis, tactical navigation support, and daily briefings for the Healy Command and Chief Scientist.

}, keywords = {arctic, ECS, Healy, Law of the Sea}, author = {Larry A Mayer and Brian R Calder and David C Mosher} } @proceedings {5704, title = {Alpha / Mendeleev Ridge and Chukchi Borderland 40Ar/39Ar Geochronology and Geochemistry: Character of the First Submarine Intraplate Lavas Recovered from the Arctic Ocean}, volume = {17}, year = {2015}, month = {April 12 - 17}, address = {Vienna, Austria}, abstract = {

At least three episodes of magmatic activity have been recognized on the basis of 40Ar/39Ar age determinations in the submarine basaltic samples dredged, drilled or grabbed with a manipulation arm from Alpha / Mendeleev Ridge and Chukchi Borderland of the Arctic Ocean by US Coast Guard Icebreaker Healy, in August-September 2008, and Russian research vessel Captain Dranitsin in August-October 2012: ca. 112 Ma, ca. 100 Ma and ca. 85-73 Ma. Major-oxide and trace-element concentrations, and Pb, Sr, Nd, and Hf isotopic ratios of the recovered lavas provide important constraints on the composition and sources for the original melts. Lavas erupted at ca. 112 Ma (Group 1) have alkali basalt major-oxide compositions. Their low degree of rare-earth-element (REE) fractionation (CeN/YbN = 1.7-2.5), combined with high overall HREE (22-24 times chondrite) and Mg$\#$ ~54, suggest derivation from a garnet-free source followed by only minimal crystal fractionation for this group. Pb-Sr-Nd-Hf isotopic systematics of the lavas (206Pb/204Pb = 18.73-18.79; 207Pb/204Pb = 15.54-15.56; 208Pb/204Pb = 38.28-38.35; 143Nd/144Nd = 0.512594-0.512610; 87Sr/86Sr = 0.709458-0.709601; 176Hf/177Hf = 0.283224), together with ratios of highly incompatible trace elements (Th/Ce = 0.09-0.11; Ce/Nb = 2.58-3.09; Th/Nb = 0.24-0.33), point toward a lithospheric source for the magmas. Eruptions at ca. 100 Ma and 85-73 Ma produced two types of lavas: low-Ti tholeiitic basalts - LT, and high-Ti alkali basalts - HT, both assigned to Group 2. This distribution of low- and high-Ti lavas is common in continental flood basalt (CFB) provinces elsewhere, and has been attributed to plume activity in some studies. The trace-element abundance patterns for these Group 2 Arctic lavas are also very similar to those of CFBs elsewhere. Their low degrees of REE fractionation (CeN/YbN = 2.0-3.3) accompanied by progressively decreasing Mg$\#$s (from 53 to 33) suggest a garnet-free source, with the derivative magmas experiencing significant crystal fractionation prior to eruption. Both LT and HT basalts have Sr, Nd and Hf isotope ratios that fall between MORB and Bulk Silicate Earth (143Nd/144Nd = 0.512669-0.512919; 87Sr/86Sr = 0.703820-0.704764; 176Hf/177Hf = 0.283128-0.283191), and are thus characterized as depleted, most likely originating in a subcontinental asthenospheric source. Contamination of these lavas with small amounts of lithospheric components is a distinct possibility. HT basalts, generally the younger of the two lava types in Group 2, are more depleted in their Nd and Sr isotopic compositions than the older LT basalts. Measured Pb-isotopic ratios plot mostly along and above the Northern Hemisphere Reference Line or NHRL (206Pb/204Pb = 18.59-19.37; 207Pb/204Pb = 15.55-15.60; 208Pb/204Pb = 38.31-38.99). Volume estimates between the Group 1 and Group 2 lavas are not yet possible to determine. However, the composition-time relationships for the lavas suggest inception of melting in the Amerasia Basin\ 

}, url = {http://meetingorganizer.copernicus.org/EGU2015/EGU2015-8291-2.pdf}, author = {Mukasa, S B and Larry A Mayer and Aviado, Kimberly and Bryce, Julie and Andronikov, A and Brumley, K and Blichert-Toft, Janne and Petrov, Oleg and Shokalsky, Sergey} } @article {5711, title = {Arctic Ocean Bathymetry: A Necessary Geospatial Framework}, volume = {68, No. 5}, year = {2015}, month = {July 2015}, pages = {41-47}, publisher = {Arctic Institute of North America}, address = {Calgary, Canada}, abstract = {

Most ocean science relies on a geospatial infrastructure that is built from bathymetry data collected from ships underway, archived, and converted into maps and digital grids. Bathymetry, the depth of the seafloor, besides having vital importance to geology and navigation, is a fundamental element in studies of deep water circulation, tides, tsunami forecasting, upwelling, fishing resources, wave action, sediment transport, environmental change, and slope stability, as well as in site selection for platforms, cables, and pipelines, waste disposal, and mineral extraction. Recent developments in multibeam sonar mapping have so dramatically increased the resolution with which the seafloor can be portrayed that previous representations must be considered obsolete. Scientific conclusions based on sparse bathymetric information should be re-examined and refined. At this time only about 11\% of the Arctic Ocean has been mapped with multibeam; the rest of its seafloor area is portrayed through mathematical interpolation using a very sparse depth-sounding database. In order for all Arctic marine activities to benefit fully from the improvement that multibeam provides, the entire Arctic Ocean must be multibeam-mapped, a task that can be accomplished only through international coordination and collaboration that includes the scientific community, naval institutions, and industry.
Key words: bathymetry; Arctic Ocean; mapping; oceanography;

}, keywords = {Arctic Ocean, bathymetry, mapping, oceanography, tectonics}, url = {http://arctic.journalhosting.ucalgary.ca/arctic/index.php/arctic/article/view/4451/4655}, author = {Martin Jakobsson and Larry A Mayer and Monahan, Dave} } @article {5706, title = {On the Existence of an East-Siberian-Chukchi Ice Sheet: New Insights from the SWERUS-C3 Expedition 2014}, year = {2015}, month = {December 14-18}, address = {San Francisco, CA}, abstract = {

The glacial history of the vast Siberian continental shelf of the Laptev and East Siberian Seas is poorly known. Most of this shelf area is shallower than 120 m implying that it was exposed land during the Last Glacial Maximum (LGM) as well as during older major Quaternary glaciations. The regional glacial and deglacial history of marine transgression has greatly influenced marine conditions of today\’s Arctic Ocean continental shelves. For example, the present extent of submarine permafrost on the shallow continental shelves is tightly linked to the glacial history, because the submarine permafrost was formed during cold conditions when sea level was low enough for the shelves to be subaerially exposed. Conversely, one explanation for lack of submarine permafrost on some shelf areas is the presence of past ice sheets. Ice sheets extending over parts of the Eastern Siberian continental shelf have been proposed in literature during LGM as well as during older Quaternary glacial periods. However, the sparsely available data from the outer continental shelf and adjacent slope of the Eastern Siberian Arctic Ocean has left the glacial history in this part largely unresolved. Here we present new geophysical mapping and sediment coring data from the shallow East Siberian shelf and adjacent slope collected during the 2014 SWERUS-C3 expedition (SWERUS-C3: Swedish \– Russian \– US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions) with Swedish icebreaker Oden. The mapping, using multibeam sonar, chirp sub-bottom profiler, and electro magnetics, in combination with new sediment cores provide information on past glacial activities, sea-level history and permafrost extent on the Eastern Siberian Arctic Ocean. Combining the new SWERUS-C3 data with previous results from this region raises the question whether an East Siberian-Chukchi ice sheet existed during LGM and/or during older glacial periods.\ 

}, keywords = {chukchi, ice sheet, swerus-c3}, url = {http://fallmeeting.agu.org/2015/}, author = {Martin Jakobsson and O{\textquoteright}Regan, M A and Kirchner, N. and Ananiev, R. and Bachman, Jan and Barrientos, Natalia and Chernykh, D. and Helen K. Coxall and Cronin, Tomas and Koshurnikov, Andrey and Lobkovsky, Leopold and Larry A Mayer and Noormets, R. and Muschitiello, Francesco and Johan Nilsson and Pearce, Christof and Semiltov, I. and Christian Stranne} } @article {5565, title = {First Bedrock Samples Dredged from Submarine Outcrops in the Chukchi Borderland, Arctic Ocean}, volume = {11, no. 1}, year = {2015}, month = {February}, pages = {76-92}, publisher = {The Geological Society of America}, abstract = {

The Chukchi Borderland, a prominent bathymetric feature within the Arctic Ocean, has been interpreted as a fragment of an undeformed continental platform sequence rifted from the passive margin of Arctic Canada. Dredges collected for the U.S. Extended Continental Shelf project aboard the icebreaker U.S. Coast Guard Cutter Healy (cruise number HLY0905) recovered hundreds of kilograms of broken crystalline basement lithologies consisting of mylonitically deformed biotite-bearing amphibolite, garnet-bearing feldspathic gneiss, and augen-bearing orthogneiss from the Chukchi Borderland. Metamorphic zircon within the amphibolite and associated leucogranitic seams within these rocks yielded U-Pb zircon ages between ca. 480 and 530 Ma. Garnet-bearing feldspathic gneisses contain variably discordant Mesoproterozoic zircon, ca. 600 Ma igneous zircon, and ca. 485\–505 Ma metamorphic overgrowths. While we interpret these gneisses as deformed and metamorphosed granitoids, they could, instead, have a very immature sedimentary protolith. The youngest rocks sampled were K-feldspar augen orthogneisses that yield ca. 430 Ma zircon crystallization ages. Whole-rock geochemistry and Sr-Nd isotopic data indicate that the orthogneisses are I-type calc-alkaline granitoids. All of the basement rocks including the orthogneisses are variably metamorphosed and mylonitized. Collectively, the U-Pb age, geochemistry, and fabric of the dredged Chukchi Borderland basement samples indicate that they represent Neoproterozoic\–Ordovician orogenic crust and Silurian arc batholithic rocks. This geologic origin is inconsistent with the Neoproterozoic to early Paleozoic passive margin history of western Arctic Canada to which the Chukchi Borderland has been previously correlated. We alternatively propose that the basement of the Chukchi Borderland is related to the peri-Laurentian composite terranes of Pearya and western Svalbard that have similar geologic histories.\ 

}, keywords = {Arctic Ocean, bedrock, chukchi, dredging}, url = {http://geosphere.gsapubs.org/content/11/1/76}, author = {Brumley, K and Miller, E L and Konstantinou, A. and Grove, M. and Meisling, K.E. and Larry A Mayer} } @article {5712, title = {High Resolution Mapping of Offshore and Onshore Glaciogenic Features in Metamorphic Bedrock Terrain, Melville Bay, Northwestern Greenland}, volume = {250}, year = {2015}, month = {December 1}, pages = {29-40}, publisher = {Elsevier}, abstract = {

Geomorphological studies of previously glaciated landscapes are important to understand how ice sheets and glaciers respond to rapidly changing climate. Melville Bay, in northwestern Greenland, contains some of the most sensitive but least studied ice sheet sectors in the northern hemisphere, where the bathymetric knowledge previously was restricted to a few sparsely distributed single beam echo soundings. We present here the results of high-resolution, geomorphological mapping of the offshore and onshore landscapes in Melville Bay using multibeam sonar and satellite data, at 5- and 10-m resolutions respectively. The results show a similar areally-scoured bedrock-dominated landscape with a glacially modified cnoc-and-lochan morphology on the inner shelf (150\–500 m depth) and on the nearby exposed coast. This is manifested by the presence of U-shaped troughs, mouton\ée-type elongated landforms, stoss-and-lee forms, and streamlined features. The submarine landscape shows features that are characteristic of bedrock in folded, faulted, and weathered metamorphic terrain, and, to a lesser extent, glacially molded bedforms; while coastal landforms exhibit higher relief, irregular-shaped basins, and more subdued fracture valleys. Although generally similar, the onshore and offshore landscapes contain examples of distinctly different landform patterns, which are interpreted to reflect a longer exposure to long-term deep weathering as well as to more recent periglacial weathering processes on land. The spatial variability in the distribution of landforms across the landscape in both study areas is mostly attributed to differences in lithological properties of the bedrock. The lack of sediment cover on the inner shelf is likely a result of a capacity for sediment erosion and removal by the West Greenland Current flowing northward over the area in combination with limited sediment supply from long sea ice-cover seasons. The distribution and orientation of the landforms in the offshore part indicate ice movement toward the NW, and suggests that this area acted as a tributary or onset region for the major paleo ice stream that formed the present day Melville Bay Trough.

}, keywords = {Combined onshore-offshore mapping, Glacial erosional landforms, High-resolution mapping, Melville Bay, northwest Greenland}, url = {http://www.sciencedirect.com/science/article/pii/S0169555X15301240}, author = {Freire, Francis F and Gyllencreutz, R. and Greenwood, S. and Larry A Mayer and Egilsson, A. and Thorsteinsson, T. and Martin Jakobsson} } @article {5713, title = {Inventory and Comparative evaluation of Seabed Mapping, Classification and Modeling Activities in the Northwest Atlantic, USA to Support Regional Ocean Planning}, volume = {100}, year = {2015}, month = {June}, pages = {133-149}, publisher = {Elsevier}, abstract = {

Efforts are in motion globally to address coastal and marine management needs through spatial planning and concomitant seabed habitat mapping. Contrasting strategies are often evident in these processes among local, regional, national and international scientific approaches and policy needs. In answer to such contrasts among its member states, the United States Northeast Regional Ocean Council formed a Habitat Working Group to conduct a regional inventory and comparative evaluation of seabed characterization, classification, and modeling activities in New England. The goals of this effort were to advance regional understanding of ocean habitats and identify opportunities for collaboration. Working closely with the Habitat Working Group, we organized and led the inventory and comparative analysis with a focus on providing processes and tools that can be used by scientists and managers, updated and adapted for future use, and applied in other ocean management regions throughout the world. Visual schematics were a critical component of the comparative analysis and aided discussion among scientists and managers. Regional consensus was reached on a common habitat classification scheme (U.S. Coastal and Marine Ecological Classification Standard) for regional seabed maps. Results and schematics were presented at a region-wide workshop where further steps were taken to initiate collaboration among projects. The workshop culminated in an agreement on a set of future seabed mapping goals for the region. The work presented here may serve as an example to other ocean planning regions in the U.S., Europe or elsewhere seeking to integrate a variety of seabed characterization, classification and modeling activities.

}, keywords = {ecosystem-based management, habitat classification, marine spatial planning, seafloormapping}, url = {http://www.sciencedirect.com/science/article/pii/S1385110114001725}, author = {Shumchenia, Emily J. and Guarinello, Marisa L. and Carey, Drew A. and Lipsky, Andrew and Jennifer K Greene and Larry A Mayer and Nixon, MatthewE. and Weber, John} } @proceedings {5710, title = {Mapping the Surficial Geology of the Arctic Ocean: A Layer for the IBCAO}, year = {2015}, month = {March 23 - 25}, publisher = {Society of Petroleum Engineers}, address = {Copenhagen, Denmark}, abstract = {

The purpose of this paper is to show early results of surficial geologic mapping of the Arctic Ocean. Analysis of subbottom profiler and multibeam bathymetric data in conjunction with the regional morphology rendered from the IBCAO data are used to map nine surficial geologic units in the Arctic Ocean. For a relatively small ocean basin, the Arctic Ocean reveals a plethora of margin and basin types reflecting both the complex tectonic origins of the basin and its diverse sedimentation history. Broad and narrow shelves were subjected to a complex ice-margin history in the Quaternary, and bear the sediment types and morphological features as a result. Some shelf areas are heavily influenced by rivers. Extensive deep water ridges and plateaus are isolated from coastal input and have a long history of hemipelagic deposition. The flanks of the basins demonstrate complex sedimentation patterns resulting from mass failures and ice-margin outflow. The deep basins of the Arctic Ocean are filled with turbidites resulting from these mass-flows and are interbedded with hemiplegic deposits.

}, author = {David C Mosher and Courtney, R.C. and Martin Jakobsson and Gebhardt, C. and Larry A Mayer} } @article {5705, title = {A Multi-Frequency Look at Gas Seeps on the East Siberian Margin}, year = {2015}, month = {December 14-18}, address = {San Francisco, CA}, abstract = {

The Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions (SWERUS-C3) is a multi-investigator, multi-disciplinary program aimed at increasing our understanding of the climate-cryosphere-carbon system of the Eastern Siberian Arctic Ocean. In 2014 SWERUS-C3 carried out a two-leg field program on the Swedish Icebreaker ODEN. A component of the SWERUS-C3 program focused on water column mapping of the spatial distribution and geologic context of gas seeps using the acoustic systems on board ODEN (12 kHz EM122 multibeam echo sounder, 2-8 kHz SBP120 subbottom profiler, and an 18 kHz EK60 split-beam sonar). On Leg 2 of the 2014 expedition, a new wideband transceiver (EK80) was added to the split-beam echo sounder and calibrated, providing the ability to measure the acoustic response of the gas seeps over a much broader range of frequencies (15-30 kHz). While the broader bandwidth unquestionably provides higher target resolution a further objective of the broadband mapping was to determine whether information on bubble size distribution could be determined so as to help model the flux of gas coming from the seeps. On Leg 2 approximately 34 seeps were mapped, mostly in the vicinity of Herald Canyon. The wide-swath, high-resolution multibeam bathymetry (from the EM122) and high-resolution chirp sub-bottom profiling (from the SBP120 multibeam sub-bottom profiler) combined with water column imaging of seeps collected at both 12 kHz (from the EM122) and 15-30 kHz (from the EK80) offer an important opportunity to understand the spatial distribution of seeps and their relationship to local and regional processes as determined from seafloor and subsurface structure, as well as to explore the potential of extracting quantitative information about the magnitude of gas transport from the seeps.\ 

}, keywords = {east siberian margin, gas seeps}, url = {http://fallmeeting.agu.org/2015/}, author = {Larry A Mayer and Elizabeth Weidner and Kevin Jerram and Thomas C Weber and Martin Jakobsson and Chernykh, D. and Ananiev, R. and Mohammad, R. and Semiltov, I.} } @article {5799, title = {A Multi-Frequency Look at Gas Seeps on the East Siberian Margin}, year = {2015}, month = {December 14-18 }, publisher = {American Geophysical Union }, address = {San Francisco, CA}, abstract = {

The Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions (SWERUS-C3)is a multi-investigator, multi-disciplinary program aimed at increasing our understanding of the climate-cryosphere-carbon system of the Eastern Siberian Arctic Ocean.In 2014, SWERUS-C3 carried out a two-leg field program on the Swedish Icebreaker ODEN. A component of the SWERUS-C3 program focused on water column mapping of the spatial distribution and geologic context of gas seeps using the acoustic systems on board ODEN(12kHzEM122 multibeam echosounder, 2-8kHzSBP120 subbottom profiler, and an 18kHzEK60split-beamsonar). On Leg 2 of the 2014 expedition, a new wide-band transceiver (EK80) was added to the split-beam echosounder and calibrated, providing the ability to measure the acoustic response of the gas seeps over a much broader range of frequencies (15-30kHz). While the broader bandwidth unquestionably provides higher target resolution, a further objective of the broadband mapping was to determine whether information on bubble size distribution could be determined so as to help model the flux of gas coming from the seeps. On Leg2, 53seeps were identified in the vicinity of Herald Canyon.The wide-swath, high-resolution multibeam bathymetry (from the EM122) and high-resolution chirp subbottom profiling (from the SBP120 multibeam subbottom profiler), combined with water column imaging of seeps collected at both 12kHz (from the EM122) and 15-30kHz (from the EK80) offer an important opportunity to understand the spatial distribution of seeps and their relationship to local and regional processes as determined from seafloor and subsurface structure, as well as to explore the potential of extracting quantitative information about the magnitude of gas transportfrom the seeps.

}, keywords = {east siberian margin, gas seeps}, url = {http://ccom.unh.edu/publications/multi-frequency-look-gas-seeps-east-siberian-margin}, author = {Elizabeth Weidner and Larry A Mayer and Thomas C Weber and Martin Jakobsson and Chernykh, D. and Ananiev, R. and Mohammad, R. and Semiltov, I.} } @article {5667, title = {Seamounts, Submarine Channels, and New Discoveries}, volume = {10, No. 3}, year = {2015}, month = {November}, pages = {1-14}, publisher = {Fisheries and Marine Institute of Memorial University of Newfoundland}, address = {St. John{\textquoteright}s, Newfoundland, Canada}, keywords = {continental shelf, seamounts, submarine channels}, author = {Andrew A. Armstrong and Larry A Mayer and James V. Gardner} } @article {5487, title = {Acoustic estimates of methane gas flux from the seabed in a 6000 km2 region of the Northern Gulf of Mexico}, volume = {15, no. 5}, year = {2014}, month = {May 29, 2014}, pages = {1911-1925}, publisher = {AGU}, abstract = {

Seeps of free methane gas escaping the seabed can be found throughout the ocean basins. To understand the role of methane gas seeps in the global carbon cycle\—including both gas added to the atmosphere and that which is dissolved and potentially oxidized in the ocean volume\—it is important to quantify the amount of methane escaping the seabed. Few large-scale mapping projects of natural methane seeps have been undertaken, however, and even among these, quantitative estimates of flux are rare. Here we use acoustic mapping techniques to survey 357 natural methane seeps in a large region (6000 km2) of the northern Gulf of Mexico and outline a general approach for methane seep mapping using a combination of multibeam and split-beam echo sounders. Using additional measurements collected with a remotely operated vehicle (ROV) together with the acoustic mapping results, we estimate the total gas flux within the 6000 km2 region to be between 0.0013 and 0.16 Tg/yr, or between 0.003 and 0.3\% of the current estimates for global seabed methane seepage rates.

}, url = {http://onlinelibrary.wiley.com/doi/10.1002/2014GC005271/full}, author = {Thomas C Weber and Larry A Mayer and Kevin Jerram and Beaudoin, Jonathan and Yuri Rzhanov and D. Lovalvo} } @article {5389, title = {Arctic Ocean Glacial History}, volume = {92}, year = {2014}, pages = {42-67}, author = {Martin Jakobsson and Andreassen, K. and Bjarndottir, L.R. and Dove, D. and Dowdeswell, J and England, J.H. and Funder, S. and Hogan, K. and Ingolfsson, O. and Jennings, A. and Larson, N.K. and Kirchner, N. and Landvik, J.Y. and Larry A Mayer and Mikkelsen, N. and Moller, P and Niessen, F. and Johan Nilsson and O{\textquoteright}Regan, M A and Polyak, Leonid and Norgaard-Pedersen, N. and Stein, R.} } @article {5181, title = {Evaluation of Arctic Multibeam Sonar Data Using Nadir Crossover Analysis and Compilation of a Full-Resolution Data Product}, volume = {66}, year = {2014}, month = {May 2014}, pages = {228-236}, publisher = {Elsevier}, abstract = {

A new high-resolution multibeam bathymetry compilation of the Arctic Ocean-United States Arctic Multibeam Compilation (USAMBC)-was created from data available through public repositories. Much of the new data was collected through dedicated mapping cruises in support of the United States effort to map regions beyond the 200nm Exclusive Economic Zone. Data quality was evaluated using nadir beam crossover error statistics, and compiled into a high-resolution product through a weighted vertical stacking algorithm.

}, keywords = {Arctic Ocean, Cross-over Analysis, Data Compilation, Extended Continental Shelf}, url = {http://www.sciencedirect.com/science/article/pii/S0098300414000284}, author = {Flinders, Ashton F and Larry A Mayer and Brian R Calder and Andrew A. Armstrong} } @article {5516, title = {First scientific dives of the Nereid Under Ice hybrid ROV in the Arctic Ocean}, year = {2014}, month = {Dec 15 - 19}, address = {San Francisco, CA}, abstract = {

The first scientific dives of the new Nereid Under Ice (NUI) hybrid ROV were conducted in the Arctic Ocean in July 2014 on RV Polarstern cruise PS86, a German-US collaboration. NUI is the latest in a family of vehicles derived from the Nereus prototype, using a single optical fiber to provide real-time telemetry to and from a battery-powered vehicle allowing much greater lateral maneuverability relative to its support ship than a conventional ROV. During PS86, dives conducted in the Arctic Ocean (typical water depths ~4000m) were completed in \>80\% ice cover beneath multi-year ice that was typically 2-4m thick (increasing to depths of up to 20m beneath ridges). Dives extended up to 800m away from the ship and, over dive durations of approximately 5 hours each, covered survey tracklines of up to 3.7km at depths varying from \“landing\” on the underside of the sea-ice to maximum depths of 45m to conduct upward looking multibeam sonar mapping. Ultimately, the vehicle will be capable of both AUV and ROV mode operations at ranges of 10-20km away from the support ship and at up to 2000m water depth (including seafloor as well as under ice operations). During the current cruise, the following major science suites were utilized to prove a range of scientific capabilities of the vehicle in ice-covered oceans: multibeam mapping of rugged topography beneath multi-year sea-ice; video- and digital still photography of the under side of the ice, biota associated with the ice-water interface (algal material) and abundant fauna in the immediately underlying water column (ctenophores, larvaceans, copepods were all notable for their abundance in our study site over the Gakkel Ridge near 83N, 6W). Other scientific activities included: vertical profiles combining CTD data with a suite of biosensors to investigate the structure of primary productivity and biogeochemical cycling in minimally distrubed areas of the sunlit under-ice water column, revealing high stratification associated with meltwater formation; lateral surveys of radiance and irradiance (together with co-registered measurements on top of the same ice-floe on our last dive) to investigate light availability and variability as a function of ice-cover. We will present examples of each of these data sets, together with an outline of suggested future activities that NUI could pursue.

}, author = {Christopher R. German and Boetius, A. and Whitcomb, Louis L and Jakuba, Michael and Bailey, J. and Judge, C. and McFarland, C. and Suman, S. and Elliott, S. and Katlein, C. and Arndt, S. and Bowen, Andrew and Dana Yoerger and Kinsey, J and Larry A Mayer and Nicolaus, M. and Laney, S. and Singh, H. and Maksym, T.L. and PS 86 Scientific Research Team} } @article {5517, title = {High-resolution Mapping of Offshore and Onshore Glaciogenic Features in Melville Bay, Northwestern Greenland}, year = {2014}, month = {Dec 15 - 19}, address = {San Francisco, CA}, abstract = {

This study presents results from high resolution mapping in the northwestern part of Greenland\’s continental shelf, offshore from the Greenland Ice Sheet. The study area is located at about 74o30\’N and 58 o40\’W where high-resolution seafloor imagery were collected from ~200-500 m water depth. These data were analyzed and compared to existing high-resolution satellite imagery of exposed glacial landforms from the nearby coastal areas. Offshore geophysical mapping equipment consisted of a Kongsberg EM2040 multibeam that was bow-mounted on the sailing vessel Explorer of Sweden together with a Seatex MRU5+ motion sensor and GPS antennas. In addition, a GAVIA autonomous underwater vehicle (AUV) from University of Iceland with installed Geoswath interfometric sonar and Marine Sonic side-scan was used. The data from these systems permitted the production of both 5-m (for the EM2040) and 2-m (for the Geoswath) resolution bathymetric grids for landform analyzes. Sediment characterization analysis was also undertaken using the co-registered backscatter data. The exposed onshore landforms were studied using data from the high-res QuickBird satellite images with a 2-m pixel resolution. Geomorphic analysis of the data shows that past tectonic and glacial scouring processes have shaped the present-day landscape in both the offshore and onshore study areas. The terrain consists of glacially eroded bedrock covered with very thin surficial sediments resembling a \‘cnoc-and-lochan\’ terrain, although the degree of erosion varies spatially, probably as a result of local variations in the rock properties. Different glacially influenced features are identified and described in the study. These features have been used to understand and infer past ice-sheet processes, particularly ice-flow direction and the extent of ice-cover on the continental shelves from previous extreme glaciation events. The backscatter information from the high-resolution interferometric sonar show fine-scale sedimentation patterns which are used to infer bottom water circulation. The study highlights that the use of the high-resolution seafloor mapping systems significantly enhance the quality of geomorphologic landform assessment.\ 

}, author = {Freire, Francis F and Gyllencreutz, R. and Greenwood, S. and Larry A Mayer and Martin Jakobsson} } @article {5518, title = {Mapping the Surficial Geology of the Arctic Ocean}, year = {2014}, month = {Dec 15 - 19}, address = {San Francisco, CA}, abstract = {

Surficial geologic mapping of the Arctic Ocean was undertaken to provide a basis for understanding different geologic environments in this polar setting. Mapping was based on data acquired from numerous icebreaker and submarine missions to the polar region. The intent was to create a geologic layer overlying the International Bathymetric Chart of the Arctic Ocean. Analysis of subbottom profiler and multibeam bathymetric data in conjunction with sediment cores and the regional morphology rendered from the IBCAO data were used to map different surficial geologic units. For a relatively small ocean basin, the Arctic Ocean reveals a plethora of margin and basin types reflecting both the complex tectonic origins of the basin and its diverse sedimentation history. Broad and narrow shelves were subjected to a complex ice-margin history in the Quaternary, and bear the sediment types and morphological features as a result. Some shelfal areas are heavily influenced by rivers. Extensive deep water ridges and plateaus are isolated from coastal input and have a long history of hemipelagic deposition. An active spreading ridge and regions of recent volcanism have volcani-clastic and heavily altered sediments. Some regions of the Arctic Ocean are proposed to have been influenced by bolide impact. The flanks of the basins demonstrate complex sedimentation patterns resulting from mass failures and ice-margin outflow. The deep basins of the Arctic Ocean are filled with turbidites resulting from these mass-flows and are interbedded with hemiplegic deposits.\ 

}, author = {David C Mosher and Martin Jakobsson and Gebhardt, C. and Larry A Mayer} } @article {5486, title = {Ocean Mapping}, volume = {9. No. 2}, year = {2014}, month = {Oct. 2014}, pages = {13-18}, publisher = {Fisheries and Marine Institute of Memorial University of Newfoundland}, address = {St. John{\textquoteright}s, Newfoundland, Canada}, author = {Larry A Mayer} } @article {5515, title = {Preliminary Polar Sea Trials of Nereid-UI: A Remotely Operated Underwater Vehicle for Oceanographic Access Under Ice}, year = {2014}, month = {Dec 15 - 19}, address = {San Francisco, CA}, abstract = {

We report the development and deployment of a remotely-controlled underwater robotic vehicle capable of being teleoperated under ice under real-time human supervision. The Nereid Under-Ice (Nereid-UI or NUI) vehicle enables exploration and detailed examination of biological and physical environments including the ice-ocean interface in marginal ice zones, in the water column of ice-covered seas, at glacial ice-tongues, and ice-shelf margins, delivering realtime high definition video in addition to survey data from on board acoustic, optical, chemical, and biological sensors. The vehicle employs a novel lightweight fiber-optic tether that will enable it to be deployed from a ship to attain standoff distances of up to 20 km from an ice-edge boundary. We conducted NUI\’s first under-ice deployments during the July 2014 F/V Polarstern PS86 expedition at 86\° N 6 W\° in the Arctic Ocean - near the Aurora hydrothermal vent site on the Gakkel Ridge approximately 200 km NE of Greenland. We conducted 4 dives to evaluate and develop NUI\’s overall functioning and its individual engineered subsystems. On each dive, dead-reckoning (Ice-locked Doppler sonar and north-seeking gyrocompass) complemented by acoustic ranging provided navigation, supporting closed-loop control of heading, depth, and XY position relative to the ice. Science operations included multibeam transects of under-ice topography, precision vertical profiles for the bio-sensor suite and IR/radiance sensor suite, IR/radiance/multibeam transects at constant depth interlaced with vertical profiles and upward-looking digital still-camera surveys of the ice, including areas rich with algal material. The fiber-optic tether remained intact throughout most of all 4 dives. Consistent with the NUI concept of operations, in 3 of 4 dives the fiber-optic tether eventually failed, and the vehicle was then commanded acoustically in a series of short-duration maneuvers to return to Polarstern for recovery. These preliminary dives ranging up to 800 m from Polarstern at a max. depth of 45 m, and traveling up to 3.7 km under moving sea ice. SUPPORT: NSF OPP (ANT-1126311), NOAA OER (NA14OAR4320158), WHOI, James Family Foundation, George Frederick Jewett Foundation East, PS86 Chief Scientist Antje Boetius, and the Captain and Crew of F/V Polarstern PS86.

}, author = {Whitcomb, Louis L and Jakuba, Michael and Christopher R. German and Bowen, Andrew and Dana Yoerger and Kinsey, J and Larry A Mayer and McFarland, C. and Suman, S. and Bailey, J. and Judge, C. and Elliott, S. and Gomez-Ibanez, D. and Taylor, Christopher and Machado, Casey and Howland, J and C.L. Kaiser and Heintz, Matthew and Pontbriand, C. and O{\textquoteright}hara, L. and McDonald, G. and Boetius, A.} } @proceedings {5398, title = {Use of seafloor stereo-images to validate automatic classification of benthic habitats}, year = {2014}, month = {May 5 - May 9}, address = {Lorne, Victoria, Australia}, abstract = {

Here we present a technique for automatic classification of seafloor data collected during the 2012 HABCAM-V4 cruises, a federally funded long term project part of the annual NOAA sea-scallop\’s survey.

This project will analyse a unique data set that includes simultaneously collected data such as:
- Hi-resolution multi-beam (digital bathymetry and backscatter intensity)
- Seafloor stereo image data (e.g. species and substrate)
- Environmental parameters (e.g. temperature, salinity, water turbidity)

The analysis will be based on an unsupervised spatial clustering (K-means) of a combination of several predictors like morphological features (curvature, rugosity, fractal index, surface area) and backscatter intensity. The final results will be validated by analysing the identified classes with a randomly selected subset of underwater photographs for each class.

The seafloor classification map produced is then used as a preliminary \"habitat classification\" for further classification. It can be reused to define selection criteria for the underwater images used by automatic classifier or by manual image annotator tools.

Results from this project will also help to define new survey track-lines prior to and during HABCAM surveys.

}, url = {http://geohab.org/conferences/2014-lorne-australia/}, author = {Massimo Di Stefano and Giuseppe Masetti and Larry A Mayer} } @article {5514, title = {What a Difference a Swath Makes!}, year = {2014}, month = {Dec 15 - 19}, address = {San Francisco, CA}, abstract = {

Since the introduction to the academic community of multibeam sonar swath mapping techniques in the late 1970s, the ability to collect high-resolution bathymetry and seafloor imagery has steadily increased. Early systems provided a limited number (e.g., 16) of relatively broad (2-4 degree) beams and swath widths of approximately one times the water depth, whereas current systems offer hundreds of narrower (0.5 to 1 degree) beams over swath widths of five to seven times water depth. Innovations like chirped pulses and high-density beam forming (multiple depth solutions per beam footprint) have also pushed the resolution of modern systems. Despite these improvements, the resolution achievable is fundamentally limited by trade-offs between beam width, bandwidth, transducer size and propagation, resulting in the need for short ranges to the seafloor to achieve the highest levels of resolution. In the deep sea this means delivery of high-frequency, high-resolution mapping systems close to the bottom by means of towed or autonomous vehicles, the trade-off here being limited areal coverage due to narrow swaths and slow mapping speeds. Despite these constraints, we cannot forget that only a small fraction of the deep ocean has been mapped by any sort of swath mapping system (10-20\%) and that even a single well-calibrated and properly operated multibeam swath collected at high-speed during a long transit can offer a remarkable amount of insight into seafloor processes. We will illustrate this through the exploration of a single transit by the R/V KILO MOANA (using a Kongsberg EM120 MBES) from Hawaii to Kodiak Alaska. When compared to the best available global bathymetric compilations using both satellite derived bathymetry and existing bathymetric data (e.g., Global Topography of Smith and Sandwell, GMRT, or ETOPO-1), the single swath offers detailed views of deep-sea channels, seamount and guyots, tectonic structure and volcanic processes that are totally absent in the compilations. Given the difference that a single swath can make in interpreting deep-sea processes, imagine what we would learn from complete coverage \– even at 100 m pixel resolution - of the deep ocean seafloor.\ 

}, author = {Larry A Mayer and James V. Gardner} } @proceedings {5160, title = {Acoustic and optical observations of methane gas seeps in the Gulf of Mexico}, volume = {19}, year = {2013}, month = {2 - 7 June}, author = {Thomas C Weber and Kevin Jerram and Yuri Rzhanov and Larry A Mayer and D. Lovalvo} } @article {5042, title = {Application of landscape mosaics for the biological quality assessment of subtidal macroalgae communities using the CFR index}, year = {2013}, keywords = {CFR index, Landscape mosaics, Sample size, Subtidal macroalgae, WaterFrameworkDirective}, url = {http://www.journals.elsevier.com/deep-sea-research-part-i-oceanographic-research-papers/}, author = {Guinda Salsamendi, Xabier and Gracia, A. and Puente, A. and Juanes, J.A. and Yuri Rzhanov and Larry A Mayer} } @proceedings {5168, title = {Arctic Ocean Bathymetry: A required geospatial framework}, year = {2013}, month = {Apr 30 - May 2}, abstract = {

Most ocean science relies largely on a geospatial infrastructure that is built primarily from bathymetry data collected underway from ships, archived, and converted into maps and digital grids. Bathymetry, the shape and composition of the seafloor, besides having vital importance to geology and navigation, is a fundamental element of studies of ocean modeling, deep water circulation, tides, tsunami forecasting, upwelling, fishing resources, wave action, sediment transport, environmental baselines, slope stability and risk, paleoceanography, site selection for platforms cables and pipelines, waste disposal, mineral extraction and sampling for environmental research. Recent developments in multibeam sonar mapping have so dramatically increased the resolution with which the seafloor can be portrayed, understood, used by other sciences and interacted with, that previous maps must be considered obsolete and scientific conclusions based on them re-examined and refined. The downside is that only about 10\% of the Arctic Ocean has been mapped with multibeam; the rest of its seafloor area is portrayed through mathematical interpolation using a very sparse depth sounding database. In order for all Arctic marine actives to benefit fully from the order of magnitude improvement that multibeam provides, the entire Arctic Ocean must be ensonified with multibeam data, a task that only can be accomplished through broad international coordination and collaboration, including both the scientific community and industry.

}, author = {Martin Jakobsson}, editor = {Larry A Mayer} } @article {5284, title = {The Caledonian suture in the high Arctic? New Data from the Chukchi Borderland, Amerasia Basin}, year = {2013}, month = {9-13 December}, address = {San Francisco, CA}, keywords = {amerasia basin, caledonian suture, chukchi}, author = {O{\textquoteright}Brien, T.M. and Brumley, K and Miller, E L and Larry A Mayer} } @proceedings {5296, title = {Challenges of defining uncertainty in multibeam sonar derived seafloor backscatter}, year = {2013}, month = {June 24-June 28}, address = {Corfu, Greece}, author = {Mashkoor A Malik and Larry A Mayer and Thomas C Weber and Brian R Calder and Huff, Lloyd C} } @article {5285, title = {Design and Fabrication of Nereid-UI: A Remotely Operated Underwater Vehicle for Oceanographic Access Under Ice}, year = {2013}, month = {9-13 December}, address = {San Francisco, CA}, keywords = {nereid-ui, under ice}, author = {Whitcomb, Louis L and Bowen, Andrew and Dana Yoerger and Christopher R. German and Kinsey, J and Larry A Mayer and Jakuba, Michael and Gomez-Ibanez, D. and Taylor, Christopher and Machado, Casey and Howland, J and C.L. Kaiser and Heintz, Matthew and Pontbriand, C. and Suman, S. and O{\textquoteright}hara, L.} } @proceedings {5288, title = {Designing Improved Sediment Transport Visualizations}, year = {2013}, month = {Sept 23-26}, publisher = {IEEE}, address = {San Diego, CA, USA}, author = {Englert, Chris and Butkiewicz, Thomas and Larry A Mayer and Arthur Trembanis and Beaudoin, Jonathan and Val Schmidt and Duval, C.} } @article {5252, title = {A detailed seabed signature from Hurricane Sandy revealed in bedforms and scour}, volume = {14}, year = {2013}, month = {10/3/2013}, publisher = {AGU and the Geochemical Society}, abstract = {

On 30 October 2012, Hurricane Sandy made landfall near Brigantine New Jersey bringing widespread erosion and damage to the coastline. We have obtained a unique set of high-resolution before and after storm measurements of seabed morphology and in situ hydrodynamic conditions (waves and currents) capturing the impact of the storm at an inner continental shelf field site known as the \‘\‘Redbird reef\’\’. Understanding the signature of this storm event is important for identifying the impacts of such events and for understanding the role that such events have in the transport of sediment and marine debris on the inner continental shelf. As part of an ONR-sponsored program designed to understand and characterize the ripple dynamics and scour processes in an energetic, heterogeneous inner-shelf setting, a series of high-resolution geoacoustic surveys were conducted before and after Hurricane Sandy. Our overall goal is to improve our understanding of bedform dynamics and spatio-temporal length scales and defect densities through the application of a recently developed fingerprint algorithm technique. Utilizing high-resolution swath sonar collected by an AUV and from surface vessel sonars, our study focuses both on bedforms in the vicinity of manmade seabed objects and dynamic natural ripples on the inner shelf in energetic coastal settings with application to critical military operations such as mine countermeasures.\ 

}, keywords = {bedforms, multibeam, Sandy, scour}, url = {http://onlinelibrary.wiley.com/doi/10.1002/ggge.20260/full}, author = {Arthur Trembanis and Duval, C. and Beaudoin, Jonathan and Val Schmidt and Miller, D. and Larry A Mayer} } @article {5273, title = {A detailed seabed signature from Hurricane Sandy revealed in bedforms and scour}, volume = {14}, year = {2013}, month = {23 Aug 2013}, pages = {4334{\textendash}4340}, publisher = {AGU}, abstract = {

On 30 October 2012, Hurricane Sandy made landfall near Brigantine New Jersey bringing widespread erosion and damage to the coastline. We have obtained a unique set of high-resolution before and after storm measurements of seabed morphology and in situ hydrodynamic conditions (waves and currents) capturing the impact of the storm at an inner continental shelf field site known as the \“Redbird reef\”. Understanding the signature of this storm event is important for identifying the impacts of such events and for understanding the role that such events have in the transport of sediment and marine debris on the inner continental shelf. As part of an ONR-sponsored program designed to understand and characterize the ripple dynamics and scour processes in an energetic, heterogeneous inner-shelf setting, a series of high-resolution geoacoustic surveys were conducted before and after Hurricane Sandy. Our overall goal is to improve our understanding of bedform dynamics and spatio-temporal length scales and defect densities through the application of a recently developed fingerprint algorithm technique. Utilizing high-resolution swath sonar collected by an AUV and from surface vessel sonars, our study focuses both on bedforms in the vicinity of manmade seabed objects and dynamic natural ripples on the inner shelf in energetic coastal settings with application to critical military operations such as mine countermeasures.

}, keywords = {AUV, Littoral processes, Submergence instruments: ROV, submersibles}, url = {http://onlinelibrary.wiley.com/doi/10.1002/ggge.20260/full}, author = {Arthur Trembanis and Duval, C. and Beaudoin, Jonathan and Val Schmidt and Miller, D. and Larry A Mayer} } @article {5281, title = {Dredged Bedrock Samples from the Amerasia Basin, Arctic Ocean}, year = {2013}, month = {9-13 December}, address = {San Francisco, CA}, keywords = {amerasian basin, Arctic Ocean, bedrock, dredging}, author = {Brumley, K and Mukasa, S B and O{\textquoteright}Brien, T.M. and Larry A Mayer and Dale N Chayes} } @article {5299, title = {Exploration of Eratosthenes Seamount {\textendash} A continental fragment being forced down an oceanic trench}, volume = {26}, year = {2013}, month = {March 2013}, pages = {36-41}, publisher = {Oceanography Society}, url = {http://www.tos.org/oceanography/archive/26-1_nautilus.pdf}, author = {Mitchell, Garrett and Larry A Mayer and Bell, K L and Nicole A Raineault and Chris Roman and Robert Ballard and Cornwell, K. and Hine, A. and Shinn, E. and Dimitriadis, I. and Bogdan, O.} } @article {5286, title = {Hurricane Sandy{\textquoteright}s Fingerprint: Ripple Bedforms at an Inner Continental Shelf Sorted Bedform Field Site}, year = {2013}, month = {9-13 December}, address = {San Francisco, CA}, author = {Duval, C. and Arthur Trembanis and Beaudoin, Jonathan and Val Schmidt and Larry A Mayer} } @article {5287, title = {Morphodynamic Impacts of Hurricane Sandy on the Inner-shelf}, year = {2013}, month = {9-13 December}, address = {San Francisco, CA}, author = {Arthur Trembanis and Beaudoin, Jonathan and Duval, C. and Val Schmidt and Larry A Mayer} } @article {5166, title = {Multibeam Echosounder System Optimization for Water Column Mapping of Undersea Gas Seeps}, year = {2013}, month = {April 16-18}, address = {Boston, MA, United States}, abstract = {

The ability to image water column scatterers has broadened the utility of multibeam echosounders and these systems, which were initially designed for hydrographic purposes, are now being used more often for physical, chemical and biological oceanographic studies of water column phenomena. It must be remembered, however, that multibeam echosounders were designed for bathymetric measurements and many features of modern systems reflect this: (1) frequency encoded, multi-sector systems are able to stabilize imaging geometry to ensure near constant sounding spacing and density on the seafloor, (2) dual swath systems allow for increased sounding density and faster survey speeds, (3) FM pulses allow for improved range performance and (4) transmit focusing improves angular resolution in the nearfield.\ These improvements to multibeam systems augment their abilities from the hydrographic point of view, however, their impact on those who wish to quantitatively study water column scatterers is poorly understood.

In this work, we discuss field trials in which a Kongsberg Maritime EM302 multibeam echosounder was optimized for water column mapping of natural seabed gas seeps through repeat observations of a known set of seeps in the Gulf of Mexico. A systematic mapping campaign immediately followed the trials with hundreds of seeps detected in area measuring ~85 km x 130 km. Of particular interest to the hydrographic community are the efforts undertaken to accurately ray trace and georeference water column scatterers as the algorithms employed can be applied to water column imaging in support of least-depth detection over wrecks and other hazards to navigation.

}, keywords = {multibeam water column gas seeps}, author = {Beaudoin, Jonathan and Thomas C Weber and Kevin Jerram and Glen A Rice and Mashkoor A Malik and Larry A Mayer} } @article {5283, title = {Scientific Discoveries in the Central Arctic Ocean Based on Seafloor Mapping Carried Out to Support Article 76 Extended Continental Shelf Claims}, year = {2013}, month = {9-13 December}, address = {San Francisco, CA}, keywords = {article 76, Extended Continental Shelf}, author = {Martin Jakobsson and Larry A Mayer and Marcussen, C} } @article {5282, title = {Utilizing New Multibeam Sonar Datasets to Map Potential Locations of Sensitive Benthic Habitats in the U.S. Atlantic Extended Continental Shelf}, year = {2013}, month = {9-13 December}, address = {San Francisco, CA}, keywords = {benthic habitat, continental shelf, multibeam sonar}, author = {Derek Sowers and Larry A Mayer and James V. Gardner} } @article {5033, title = {Acoustic observations of oil and gas in the northern Gulf of Mexico during and after the Deepwater Horizon spill}, year = {2012}, month = {28 March}, author = {Thomas C Weber and Larry A Mayer and De Robertis, Alex and Greenaway, Samuel F and Glen A Rice and Beaudoin, Jonathan and Shedd, B.} } @proceedings {5030, title = {Acoustic sensing of gas seeps in the deep ocean with split-beam echosounders}, year = {2012}, month = {July 2 - July 6}, keywords = {gas seeps}, author = {Thomas C Weber and Kevin Jerram and Larry A Mayer} } @proceedings {4891, title = {Application of Landscape Mosaics for the Ecological Status Assesment of Subtidal Macroalgae Communities Using the CFR Index}, year = {2012}, month = {Apr 4 - Apr 11}, address = {Santander, Spain}, keywords = {Seafloor Characterization - Optical Imagery}, url = {www.ieo-santander.net/isobay13/}, author = {Gracia, A. and Guinda Salsamendi, Xabier and Juanes, J.A. and Yuri Rzhanov and Larry A Mayer} } @inbook {5070, title = {Arctic Marine Research: A U.S. Practitioner{\textquoteright}s Perspective}, booktitle = {Arctic Science, International Law and Climate Change}, number = {235}, year = {2012}, pages = {83-95}, publisher = {Springer Heidleberg}, organization = {Springer Heidleberg}, address = {Berlin, Germany}, author = {Larry A Mayer} } @article {5043, title = {Combining angular and spatial information from multibeam backscatter data for improved unsupervised acoustic seabed segmentation}, year = {2012}, month = {February 21-24}, address = {Wellington, New Zealand}, url = {http://www.conference.co.nz/shallowsurvey}, author = {Alexandre C. G. Schimel and Yuri Rzhanov and Fonseca, Luciano and Larry A Mayer and Immenga, Dirk} } @inbook {4266, title = {The Continental Shelf and Changing Sea Level}, booktitle = { Maritime Boundary Diplomacy, Center for Oceans Law and Policy Series}, number = {16}, year = {2012}, month = {09/2012}, pages = {197-212}, publisher = {Martinus Nijhoff Publishers}, organization = {Martinus Nijhoff Publishers}, abstract = {

This chapter discusses the changes seen in the Arctic and the impact that these changes are having on maritime boundary issues. It looks at how the forces that are driving the changes we are seeing in the Arctic are also having a global impact on maritime boundary issues, raising in particular, issues related to the continental shelf. Global sea level rise has an immediate impact on maritime boundaries through the definition of the baselines from which the maritime zones are measured. Given the potential for a significant rise in sea level and with that, the potential for migrating and potentially disappearing baselines, the chapter discusses the ramification when the continental shelf outer limit is \“fixed and binding\” and \“permanent. The chapter discusses a simple hypothetical case of the small Japanese island, Minamitorishima, in the northwest Pacific located approximately 1150 miles southeast of Tokyo.\ 

}, keywords = {continental shelf; maritime boundaries; Minamitorishima; sea level}, doi = {10.1163/9789004230941_015}, author = {Larry A Mayer}, editor = {Nordquist, M. and Moore, J. Norton} } @inbook {5071, title = {Deepwater Horizon and the Arctic: Is there a Need for International Regulation?}, booktitle = {The Law of the Sea Convention: U.S. Accession and Globalization}, year = {2012}, pages = {512 - 528}, publisher = {Martinus Nijhoff Publishers}, organization = {Martinus Nijhoff Publishers}, edition = {Center for Oceans Law and Policy Series}, address = {Leiden, South Holland, The Netherlands}, author = {Larry A Mayer and Roach, J A and Baker, B} } @article {5076, title = {Development of Nereid-UI: A Remotely Operated Underwater Vehicle for Oceanographic Access Under Ice}, year = {2012}, month = {Dec 3 - Dec 7}, address = {San Francisco, CA, United States}, abstract = {

Abs. $\#$ C13E-0654

}, author = {Whitcomb, Louis L and Bowen, Andrew and Dana Yoerger and Christopher R. German and Kinsey, J and Larry A Mayer and Jakuba, Michael and Gomez-Ibanez, D. and Taylor, Christopher and Machado, Casey and Howland, J and Kaiser, Karl and Heintz, Matthew} } @article {5078, title = {Exploration of the Black, Aegean, and Mediterranean Seas Aboard E/V Nautilus}, year = {2012}, month = {Dec 3 - Dec 7}, address = {San Francisco, CA, United States}, abstract = {

Abs. $\#$ OS51D-1911

}, author = {Bell, K L and Robert Ballard and Brennan, M. L. and Nicole A Raineault and Shank, T M and Larry A Mayer and Chris Roman and Mitchell, Garrett and Coleman, D. F.} } @article {5040, title = {Exploring Eratosthenes Seamount with Deep Submergence Vehicles, Telepresence, and the E/V Nautilus}, year = {2012}, month = {October, 14-19}, address = {Hampton Roads, VA, USA}, url = {http://www.oceansconference.org/}, author = {Mitchell, Garrett and Larry A Mayer and Yuri Rzhanov} } @article {4958, title = {Geological interpretation of a low-backscatter anomaly found on the New Jersey continental margin}, volume = {326-328}, year = {2012}, month = {24-08-2012}, pages = {46-54}, publisher = {Elsevier}, abstract = {

An enigmatic low-backscatter, acoustic anomaly occurs on the New Jersey continental margin between Hudson and Wilmington Canyon channels. The presence of the low-backscatter anomaly, as seen with 6.5- and 12-kHz data, indicates a change in the physical properties of the seafloor or near sub-surface. Analyses of seafloor and sub-surface acoustic data with previously collected sediment cores suggest the low-backscatter feature corresponds to an outcrop of older strata uncovered by erosion and non-deposition by the Western Boundary Undercurrent (WBUC). The decrease in backscatter strength is enhanced by the presence of gas in the sub-surface sediments found in the buried Chesapeake Drift.\ 

}, keywords = {Chesapeake Drift, continental slope, multibeam backscatter, submarine canyons, U.S. mid-Atlantic continental margin, Western Boundary Undercurrent}, author = {Sweeney, Ed and James V. Gardner and Johnson, Joel and Larry A Mayer} } @article {4959, title = {The International Bathymetric Chart of the Arctic Ocean (IBCAO) version 3.0}, volume = {39}, year = {2012}, abstract = {

The International Bathymetric Chart of the Arctic Ocean (IBCAO) released its first gridded\ bathymetric compilation in 1999. The IBCAO bathymetric portrayals has since supported a wide\ range of Arctic science activities, for example, by providing constraint for ocean circulation models and the means to define and formulate hypotheses about the geologic origin of the Arctic Ocean undersea features. IBCAO Version 3.0 comprises the largest improvement since 1999 taking advantage of new data sets collected by the circum-Arctic nations, opportunistic data collected from fishing vessels, data acquired from US Navy submarines and from research ships of various nations. Built using an improved gridding algorithm, this new grid is on a 500 meter spacing, revealing much greater details of the Arctic seafloor than IBCAO 1.0 (2.5 km) and 2.0 (2.0 km). The area covered by multibeam surveys has increased from ~6 \% in Version 2.0 to ~11\% in Version 3.0.

}, keywords = {Arctic Ocean, bathymetric chart, Bathymetry grids; Arctic; Earth Sciences, ibcoa}, author = {Martin Jakobsson and Larry A Mayer and Coakley, Bernie and Dowdeswell, J and Forbes, S. and Fridman, B. and Hodnesdal, H. and Noormets, R. and James V. Gardner and Andrew A. Armstrong and Pedersen, R. and M. Rebesco and Schenke, H-W. and Zarayskaya, Yulia and Accettella, D. and Anderson, Robert M and Bienhoff, P. and Camerlenghi, A. and Church, I and Edwards, Margo and John K Hall and Hell, B and Hestvik, O. and Kristoffersen, Yngue and Marcussen, C and Mohammad, R. and David C Mosher and Nghiem, S.V. and Pedrosa, M.T. and Travaglini, P.G. and Pauline Weatherall} } @proceedings {4893, title = {Landscape Mosaicing Techniques Versus Traditional Sampling Procedures for the Assessment of Subtidal Macroalgae Communities}, year = {2012}, month = {Jun 3 - Jun 7}, address = {Venice, Italy}, keywords = {Seafloor Characterization - Optical Imagery}, url = {www.estuarinecoastalconference.com}, author = {Guinda Salsamendi, Xabier and Gracia, A. and Puente, A. and Juanes, J.A. and Yuri Rzhanov and Larry A Mayer} } @article {5158, title = {Mapping Gas Seeps with the Deepwater Multibeam Echosounder on Okeanos Explorer}, volume = {25}, year = {2012}, author = {Thomas C Weber and Larry A Mayer and Beaudoin, Jonathan and Kevin Jerram and Mashkoor A Malik and Shedd, B. and Glen A Rice} } @article {4965, title = {Multibeam Echosounder System Optimization for Water Column Mapping of Undersea Gas Seeps}, year = {2012}, month = {May 15-17}, address = {Niagara Falls, Ontario, Canada}, keywords = {Mid-Water Mapping}, author = {Beaudoin, Jonathan and Thomas C Weber and Kevin Jerram and Glen A Rice and Mashkoor A Malik and Larry A Mayer} } @article {5077, title = {Quality Assessment of GEBCO 08, Smith and Sandwell and SRTM30 Plus Grids in the Arctic}, year = {2012}, month = {Dec 3 - Dec 7}, address = {San Francisco, CA, United States}, abstract = {

Abs. $\#$ OS51D-1905

}, author = {Abramova, Anastasia and Monahan, Dave and Larry A Mayer and Thomas C Lippmann and Brian R Calder} } @article {5072, title = {Recent Advantages in Ocean Mapping}, volume = {7, no. 2}, year = {2012}, pages = {1 - 12}, author = {Larry A Mayer} } @article {5075, title = {Re-evaluating Amerasian Basin tectonics and sedimentation with new geophysical data}, year = {2012}, month = {Aug 5 - Aug 10}, address = {Brisbane, Australia}, author = {David C Mosher and Shimeld, J and Hutchinson, D R and Jackson, R and Chian, D and Lebedeva-Ivanova, N. and Oakey, G. and Evangaletos, J. and Li, Q. and Funct, T. and Larry A Mayer and Verhoef, J and Forbes, S.} } @article {5028, title = {Scientific basis for safely shutting in the Macondo Well after the April 20, 2010 Deepwater Horizon blowout}, year = {2012}, abstract = {

As part of the government response to the Deepwater Horizon blowout, a Well Integrity Team evaluated the geologic hazards of shutting in the Macondo Well at the seafloor and determined the conditions under which it could safely be undertaken. Of particular concern was the possibility that, under the anticipated high shut-in pressures, oil could leak out of the well casing below the seafloor. Such a leak could lead to new geologic pathways for hydrocarbon release to the Gulf of Mexico. Evaluating this hazard required analyses of 2D and 3D seismic surveys, seafloor bathymetry, sediment properties, geophysical well logs, and drilling data to assess the geological, hydrological, and geomechanical conditions around the Macondo Well. After the well was successfully capped and shut in on July 15, 2010, a variety of monitoring activities were used to assess subsurface well integrity. These activities included acquisition of wellhead pressure data, marine multichannel seismic profiles, seafloor and water-column sonar surveys, and wellhead visual/acoustic monitoring. These data showed that the Macondo Well was not leaking after shut in, and therefore, it could remain safely shut until reservoir pressures were suppressed (killed) with heavy drilling mud and the well was sealed with cement.

}, url = {http://www.pnas.org/content/early/2012/11/28/1115847109.abstract}, author = {Hickman, Stephen H. and Hsieh, Paul A. and Mooney, Walter D. and Enomoto, Catherine B. and Nelson, Philip H. and Larry A Mayer and Thomas C Weber and Moran, Kathryn and Flemings, Peter B. and McNutt, Marcia K.} } @article {5055, title = {Sediment Mixing in the Tropical Pacific and Radiolarian Stratigraphy}, year = {2012}, author = {Moore, T.C. and Larry A Mayer and Lyle, Mitchell} } @article {5074, title = {Status of U.S. Mapping Activities in the Arctic}, year = {2012}, month = {Nov 6}, address = {Portsmouth, NH, USA}, author = {Larry A Mayer and Andrew A. Armstrong and Hutchinson, D R and Van Pay, B. and Moore, B.} } @article {5084, title = {U.S. Law of the Sea Cruise to Map and Sample the US Arctic Ocean Margin}, year = {2012}, pages = {159}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {arctic, ECS, Healy, Law of the Sea, unclos}, author = {Larry A Mayer and Andrew A. Armstrong} } @inbook {4267, title = {A U.S. Practitioner{\textquoteright}s Perspective}, booktitle = {Contributions on Comparative Public Law and International Law, Max Plank Institute}, year = {2012}, author = {Larry A Mayer} } @article {4322, title = {Acoustic observations of the deep scattering layer during the Deepwater Horizon oil spill}, year = {2011}, month = {23-27 May}, address = {Seattle, WA, USA}, author = {De Robertis, Alex and Thomas C Weber and Larry A Mayer and Christopher D Wilson} } @article {4295, title = {Comparison and evaluation of publicly available grids in the Arctic}, year = {2011}, month = {6th Bathymetric Science Day, GEBCO}, keywords = {Deep ocean bathymetry}, url = {http://www.gebco.net/about_us/gebco_science_day/documents/gsd_2011_poster_abramova.pdf}, author = {Abramova, Anastasia and Thomas C Lippmann and Brian R Calder and Larry A Mayer and Monahan, Dave} } @article {4306, title = {Construction of seafloor thematic maps from multibeam acoustic backscatter angular response data}, year = {2011}, month = {09/2011}, publisher = {Elsevier}, address = {Cambridge, MA, USA}, keywords = {Data Processing, GeoCoder, Seafloor Characterization}, author = {Yuri Rzhanov and Fonseca, Luciano and Larry A Mayer} } @article {4324, title = {Detecting and mapping gas seeps with a deepwater multibeam echosounder}, year = {2011}, month = {8-9 November}, address = {Houston, TX, USA}, author = {Thomas C Weber and Beaudoin, Jonathan and Shedd, B. and Mashkoor A Malik and Kevin Jerram and Glen A Rice and Larry A Mayer} } @article {4264, title = {Estimating oil concentration and flow rate with calibrated vessel-mounted acoustic echo sounders}, volume = {108}, year = {2011}, month = {12/2011}, abstract = {

As part of a larger program aimed at evaluating acoustic techniques for mapping the distribution of subsurface oil and gas associated with the Deepwater Horizon-Macondo oil spill, observations were made on June 24 and 25, 2010 using vessel-mounted calibrated single-beam echo sounders on the National Oceanic and Atmospheric Administration ship Thomas Jefferson. Coincident with visual observations of oil at the sea surface, the 200-kHz echo sounder showed anomalously high-volume scattering strength in the upper 200\ m on the western side of the wellhead, more than 100 times higher than the surrounding waters at 1,800-m distance from the wellhead, and weakening with increasing distance out to 5,000\ m. Similar high-volume scattering anomalies were not observed at 12 or 38\ kHz, although observations of anomalously low-volume scattering strength were made in the deep scattering layer at these frequencies at approximately the same locations. Together with observations of ocean currents, the acoustic observations are consistent with a rising plume of small (\<\ 1-mm radius) oil droplets. Using simplistic but reasonable assumptions about the properties of the oil droplets, an estimate of the flow rate was made that is remarkably consistent with those made at the wellhead by other means. The uncertainty in this acoustically derived estimate is high due to lack of knowledge of the size distribution and rise speed of the oil droplets. If properly constrained, these types of acoustic measurements can be used to rapidly estimate the flow rate of oil reaching the surface over large temporal and spatial scales.

}, keywords = {Acoustic Echo Sounders, Deepwater Horizon, Oil Concentration, Vessel-Mounted Acoustic Echo Sounders}, url = {http://www.pnas.org/content/early/2011/12/07/1108771108.full.pdf+html}, author = {Thomas C Weber and De Robertis, Alex and Greenaway, Samuel F and Smith, Shep M and Larry A Mayer and Glen A Rice} } @article {4328, title = {New Frontiers in Ocean Exploration: The 2011 E/V NAUTILUS Field Season}, year = {2011}, month = {5-9 December 2011}, address = {San Francisco, CA, USA}, abstract = {

2011 Fall Meeting, AGU Identifier: Abstract OS21A-1570

}, keywords = {EV Nautilus, Ocean exploration}, author = {Bell, K L and Robert Ballard and Coleman, D. F. and Chris Roman and Brennan, M. L. and Turanli, T and Duman, M. and Carey, S. and Nomikou, P and Marani, M. and Rosi, M. and Austin, J. A. and Canals, M. and Karson, J and Larry A Mayer and Makovsky, Y.} } @article {4327, title = {Petrography and U-Pb zircon geochronology of Caledonian age orthogneisses dredged from the Chukchi Borderland, Arctic Ocean}, year = {2011}, month = {5-9 December 2011}, address = {San Francisco, CA, USA}, abstract = {

2011 Fall Meeting AGU Identifier Number: Abstract T51K-07

}, keywords = {Arctic Ocean, Chukchi Borderland, geochronology, Petrography}, author = {Brumley, K and Miller, E L and Larry A Mayer and Wooden, J L and Dumitru, T A} } @article {3912, title = {U.S. Law of the Sea Cruise to Map the Foot of the Slope and 2500-m Isobath of the U.S. Arctic Ocean Margin}, year = {2011}, pages = {1-235}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Law of the Sea}, author = {Larry A Mayer and Andrew A. Armstrong} } @article {, title = {Petrography and U-pb, Detrital Zircon Geochronology of Metasedimentary Strata Dredged from the Chukchi Borderland, Amerasia Basin, Arctic Ocean}, year = {2010}, month = {Dec 13 - Dec 17}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Brumley, K and Miller, E L and Larry A Mayer and Andronikov, A and Wooden, J L and Dumitru, T A and Elliott, B and Gehrels, G E and Mukasa, S B} } @article {, title = {New Frontiers in Ocean Exploration:\  The 2010 E/V Nautilus Field Season}, year = {2010}, month = {Dec 13 - Dec 17}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Bell, K L and Robert Ballard and Coleman, D. F. and Chris Roman and Brennan, M. L. and Turanli, T and Carery, S and Nomikou, P and Vougioukalakis, G and Larry A Mayer and Nicolaides, S and Konnaris, K and Shank, T M and Austin, J. A. and Ben-Avraham, Z and Phillips, B} } @article {, title = {Observations Near the Well Head using Vessel Mounted Scientific Echo Sounders}, year = {2010}, month = {Nov 15 - Nov 19}, chapter = {160th Meeting}, address = {Cancun, Quintana Roo, Mexico}, keywords = {Other}, author = {Thomas C Weber and Larry A Mayer and Greenaway, Samuel F and De Robertis, Alex and Christopher D Wilson and Smith, Shep M and Glen A Rice} } @article {, title = {Sedimentation in Canada Basin, Western Arctic}, year = {2010}, month = {Dec 13 - Dec 17}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {David C Mosher and Shimeld, J and Jackson, R and Hutchinson, D R and Chapman, B and Chian, D and Childs, J R and Larry A Mayer and Edwards, D B and Verhoef, J} } @article {, title = {Remote Acoustic Characterization of Seafloor Properties from an AUV}, year = {2010}, month = {Feb 22 - Feb 26}, chapter = {2010}, address = {Portland, OR, USA}, keywords = {AUV \& Harbor Tracking}, author = {Arthur Trembanis and Larry A Mayer and Nicole A Raineault and Val Schmidt and Yuri Rzhanov and Brian R Calder} } @proceedings {, title = {Correction of Bathymetric Survey Artifacts Resulting from Apparent Wave-Induced Vertical Position of an AUV}, year = {2010}, month = {Jun 21 - Jun 23}, address = {Quebec City, Quebec, Canada}, keywords = {Other}, author = {Val Schmidt and Nicole A Raineault and Skarke, Adam and Arthur Trembanis and Larry A Mayer} } @article {, title = {An Arctic Ice Shelf During MIS 6 Constrained by New Geophysical and Geological Data}, volume = {29}, number = {25}, year = {2010}, pages = {3505-3517}, publisher = {Wiley}, keywords = {Other}, author = {Martin Jakobsson and Johan Nilsson and O{\textquoteright}Regan, M A and Backman, Jan and Lowemark, L and Dowdewell, J and Larry A Mayer and Polyak, Leonid and Colleoni, F and Anderson, L and Bjork, G and Darby, D and Eriksson, J and Hanslik, D and Hell, B and Marcussen, C and Sellen, E and Wallin, A} } @article {, title = {A New Look at Northwind Ridge: Implications for the History of the Canada Basin}, year = {2010}, month = {Dec 13 - Dec 17}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Hutchinson, D R and David C Mosher and Shimeld, J and Jackson, R and Chian, D and Edwards, D B and Hart, P E and Larry A Mayer} } @inbook {, title = {Seafloor Mapping and Exploration in a Changing Arctic Sea Ice Environment}, booktitle = {Changes in the Arctic Environment and the Law of the Sea}, volume = {33}, year = {2010}, pages = {83-106}, publisher = {Martinus Nijhoff legacy_publishers}, organization = {Martinus Nijhoff legacy_publishers}, address = {Leiden, South Holland, The Netherlands}, keywords = {Other}, author = {Larry A Mayer} } @article {, title = {More than the Bottom: Multibeam Sonars and Water-column Imaging}, year = {2010}, month = {Dec 13 - Dec 17}, pages = {1-1}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Larry A Mayer and Thomas C Weber and James V. Gardner and Mashkoor A Malik and Beaudoin, Jonathan and Doucet, Maurice} } @article {, title = {Marine Benthic Habitat Mapping of Muir Inlet, Glacier Bay National Park and Preserve, Alaska, with an Evaluation of the Coastal and Marine Ecological Classification Standard III}, year = {2010}, institution = {U.S. Geological Survey (USGS)}, address = {Scientific Investigations Map 3122}, keywords = {Other}, author = {Trusel, L D and Cochrane, G R and Etherington, L and Powell, Ross D and Larry A Mayer} } @article {3901, title = {Correction of Bathymetric Artifacts Resulting from Surface-Wave Inducted Modulations of an AUV Pressure Sensor}, year = {2010}, pages = {1-13}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {AUV \& Harbor Tracking}, author = {Val Schmidt and Nicole A Raineault and Skarke, Adam and Arthur Trembanis and Larry A Mayer} } @article {5010, title = {Multibeam mapping of the United States continental margin: Supporting the effort to delinieate the extended continental shelf under Article 76 of the United Nations Convention on the Law of the Sea}, year = {2010}, month = {2010}, address = {Cape Town, South Africa}, author = {Andrew A. Armstrong}, editor = {Larry A Mayer} } @article {2873, title = {Seafloor Mapping In The Arctic:Support For a Potential US Extended Continental Shelf}, volume = {3}, year = {2010}, pages = {14-23}, publisher = {Geomatics Information \& Trading Center - GITC}, address = {Lemmers, Amsterdam, The Netherlands}, keywords = {Law of the Sea}, author = {Larry A Mayer and Andrew A. Armstrong and Brian R Calder and James V. Gardner} } @article {, title = {Measurements of Acoustic Backscatter and Density of Captive Atlantic Cod with Synchronized 300-kHz Multibeam and 120-kHz Split-Beam Echosounders}, volume = {66}, year = {2009}, pages = {1303-1309}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Water Column Mapping}, author = {Gurshin, C W and Jech, J M and Howell, W H and Thomas C Weber and Larry A Mayer} } @article {, title = {Correction of Bathymetric Survey Artifacts Resulting from Apparent Wave-induced Vertical Movement of an AUV}, year = {2009}, pages = {1-10}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {AUV \& Harbor Tracking}, author = {Val Schmidt and Nicole A Raineault and Skarke, Adam and Arthur Trembanis and Larry A Mayer} } @article {, title = {Okeanos Explorer - Aligning Today{\textquoteright}s Technology to a New Paradigm of Ocean Exploration}, year = {2009}, month = {Apr 21 - Apr 24}, address = {Lisbon, Lisbon, Portugal}, keywords = {Other}, author = {Mashkoor A Malik and Weirich, J and Russel, Craig and Stuart, Elaine and Colleen Peters and Larry A Mayer and Andrew A. Armstrong} } @proceedings {, title = {High-resolution Delineation of Acoustically Homogeneous Areas in Multibeam Backscatter Maps}, year = {2009}, month = {Oct 4 - Oct 9}, address = {St. Andrews, New Brunswick, Canada}, keywords = {GeoCoder}, author = {Yuri Rzhanov and Fonseca, Luciano and Larry A Mayer} } @article {, title = {Effects of a Large Fishing Closure on Benthic Communitites in the Western Gulf of Maine: Recovery from the Effects of Gillnets and Otter Trawls}, volume = {107}, number = {3}, year = {2009}, pages = {308-317}, publisher = {National Marine Fisheries Service Scientific Publications Office}, keywords = {Other}, author = {Raymond E Grizzle and Larry G Ward and Larry A Mayer and Mashkoor A Malik and Cooper, Andrew B and Abeels, Holly A and Jennifer K Greene and Brodeur, Melissa A and Rosenberg, Andrew A} } @proceedings {, title = {Advanced Mid-Water Tools for 4D Marine Data Fusion and Visualization}, year = {2009}, month = {Oct 26 - Oct 29}, address = {Biloxi, MS, USA}, keywords = {Other}, author = {Doucet, Maurice and Lindsay Gee and Thomas C Weber and Roland Arsenault and Larry A Mayer and Colin Ware and Mashkoor A Malik} } @article {2845, title = {Angular Range Analysis of Acoustic Themes from Stanton Banks Ireland: A Link Between Visual Interpretation and Multibeam Echosounder Angular Signatures}, volume = {70}, year = {2009}, pages = {1298-1304}, publisher = {Association for Computing Machinery (ACM)}, address = {New York, NY, USA}, keywords = {Seafloor Characterization}, author = {Fonseca, Luciano and Craig Brown and Brian R Calder and Larry A Mayer and Yuri Rzhanov} } @proceedings {3200, title = {Mapping in the Arctic Ocean in Support of a Potential Extended Continental Shelf}, year = {2009}, month = {May 11 - May 14}, pages = {0-13}, address = {Norfolk, VA, USA}, keywords = {Law of the Sea}, author = {Larry A Mayer and Andrew A. Armstrong and James V. Gardner} } @article {3897, title = {U.S. Law of the Sea cruise to map the foot of the slope and 2500-m isobath of the US Arctic Ocean margin, cruise report for 2009}, year = {2009}, pages = {1-118}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Law of the Sea}, author = {Larry A Mayer and Andrew A. Armstrong} } @article {, title = {Detecting bedform migration in Portsmouth Harbor, New Hampshire, USA, on relatively short spatial and temporal scales}, year = {2008}, month = {Dec 15 - Dec 19}, address = {San Francisco, CA, USA}, keywords = {Multibeam Sonars}, author = {Felzenberg, Janice and Larry G Ward and Yuri Rzhanov and Irish, James D and Larry A Mayer} } @article {, title = {Glaciogenic Bedforms on the Chukchi Borderland, Morris Jesup Rise and Yermak Plateau: Three Prolongations of the Arctic Ocean Continental Margin}, year = {2008}, month = {Dec 15 - Dec 19}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Martin Jakobsson and Larry A Mayer} } @article {, title = {An Improved Bathymetric Portrayal of the Arctic Ocean: Implications for Ocean Modeling and Geological, Geophysical and Oceanographic Analyses}, volume = {35}, year = {2008}, pages = {0-1}, publisher = {American Geophysical Union }, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Martin Jakobsson and Macnab, Ron and Larry A Mayer and Anderson, Robert M and Edwards, Margo and Hatzky, Jorn and Schenke, H-W. and Paul Johnson} } @article {, title = {Dredged Rock Samples from the Alpha Ridge, Arctic Ocean: Implications for the Tectonic History and Origin of the Amerasian Basin}, volume = {89}, number = {53}, year = {2008}, month = {Dec 15 - Dec 19}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Brumley, K and Larry A Mayer and Miller, E L and Coakley, Bernie} } @proceedings {, title = {Observations of High Frequency, Long Range Acoustic Propagation in a Harbor Environment}, year = {2008}, month = {Aug 25 - Aug 28}, chapter = {1st International Conference and Exhibition}, address = {Copenhagen, Copenhagen, Denmark}, keywords = {Other}, author = {Weirathmueller, Michelle and Thomas C Weber and Larry A Mayer} } @article {, title = {Detecting bedform migration in Portsmouth Harbor on relatively short time-scales from high-resolution multibeam bathymetry}, year = {2008}, month = {Oct 21 - Oct 24}, edition = {5th}, chapter = {International}, address = {Durham, NH, USA}, keywords = {Multibeam Sonars}, author = {Felzenberg, Janice and Larry G Ward and Yuri Rzhanov and Larry A Mayer} } @article {, title = {Development of Advanced Technologies for Surveying Sea Scallops and Other Benthic Organisms}, year = {2008}, month = {Jun 12 - Jun 18}, edition = {9th Annual}, address = {San Francisco, CA, USA}, keywords = {Optical Imagery}, author = {Gallager, S and York, A and Howland, J and Taylor, R and Vine, N and Prasad, L and Swaminagayan, S and Larry A Mayer and Yuri Rzhanov and Rosencranz, G and Hart, D and Rago, P} } @article {, title = {Approaches and Requirements of Quantitative Comparison of the Multibeam Sonar Benthic Acoustic Backscatter}, year = {2008}, month = {Oct 21 - Oct 24}, edition = {5th}, chapter = {International}, address = {Durham, NH, USA}, keywords = {Multibeam Sonars}, author = {Mashkoor A Malik and Larry A Mayer and Fonseca, Luciano and Larry G Ward and Huff, Lloyd C and Brian R Calder} } @article {, title = {High-frequency One-way Propagation Experiments in Portsmouth Harbor, NH}, year = {2008}, month = {Nov 10 - Nov 14}, address = {Miami, FL, USA}, keywords = {Other}, author = {Thomas C Weber and Weirathmueller, Michelle and Larry A Mayer} } @article {, title = {Quantification of Glacimarine Sediment Yields Using Multibeam Sonar in Alaskan Fjords}, volume = {89}, number = {53}, year = {2008}, month = {Dec 15 - Dec 19}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Trusel, L D and Willems, Bryce A and Powell, Ross D and Larry A Mayer} } @article {, title = {Going Autonomous Seafloor Mapping from an AUV, Recent Results and Challenges}, year = {2008}, month = {Oct 21 - Oct 24}, edition = {5th}, chapter = {International}, address = {Durham, NH, USA}, keywords = {AUV \& Harbor Tracking}, author = {Arthur Trembanis and Hiller, T and Fonseca, Luciano and Larry A Mayer} } @proceedings {3176, title = {From the Arctic to the Tropics: The U.S. UNCLOS Bathymetric Mapping Program}, year = {2008}, month = {May 5 - May 8}, pages = {1-11}, address = {Victoria, British Columbia, Canada}, keywords = {Law of the Sea}, author = {James V. Gardner and Larry A Mayer and Andrew A. Armstrong} } @proceedings {4994, title = {From the Arctic to the tropics: The U.S. UNCLOS bathymetryic mapping program.}, year = {2008}, month = {May 5-May 8}, keywords = {Law of the Sea, unclos}, author = {James V. Gardner and Larry A Mayer and Andrew A. Armstrong} } @article {3508, title = {Recent Mapping and Sampling on the Chukchi Borderland and Alpha/Medeleev Ridge}, volume = {89}, number = {53}, year = {2008}, month = {Dec 15 - 19}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Larry A Mayer and Brumley, K and Andronikov, A and Dale N Chayes and Andrew A. Armstrong and Brian R Calder and John K Hall and Clyde, W C and Bothner, W A and James V. Gardner} } @article {5000, title = {Recent Mapping and Sampling on the Chukchi Borderland and Alpha/Medeleev Ridge}, year = {2008}, month = {December 2008}, address = {San Francisco, CA, United States}, author = {Larry A Mayer}, editor = {Brumley, K} } @article {3879, title = {U.S. Law of the Sea Cruise to Map the Foot of the Slope and 2500-m Isobath of the U.S. Arctic Ocean Margin. Cruise Report for 2008}, year = {2008}, pages = {1-179}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Law of the Sea}, author = {Larry A Mayer and Andrew A. Armstrong} } @article {2835, title = {US UNCLOS Multibeam Data: The Processing of Multibeam Bathymetry and Backcatter}, volume = {8}, number = {9}, year = {2008}, pages = {14-17}, publisher = {Geomatics Information \& Trading Center - GITC}, address = {Lemmers, Amsterdam, The Netherlands}, keywords = {Law of the Sea}, author = {Andrew A. Armstrong and Brian R Calder and Fonseca, Luciano and James V. Gardner and Larry A Mayer} } @article {, title = {Investigation of Seabed Fishing Impacts on Benthic Structure using Multi-beam Sonar, Sidescan Sonar, and Video}, volume = {64}, year = {2007}, pages = {1053-1065}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Other}, author = {Mashkoor A Malik and Larry A Mayer} } @article {, title = {Drowned shelf-edge delta complexes and barrier islands and related features along the outer continental shelf north of the head of De Sotot Canyon, NE Gulf of Mexico}, volume = {89}, year = {2007}, pages = {370-390}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Other}, author = {James V. Gardner and Brian R Calder and John E. Hughes Clarke and Larry A Mayer and Elston, Gareth R and Yuri Rzhanov} } @article {, title = {Dissolution of biogenic ooze over basement edifices in the equatorial Pacific with implications for hydrothermal ventilation of the oceanic crust}, volume = {35}, number = {8}, year = {2007}, pages = {679-682}, publisher = {The Geological Society of America (GSA)}, keywords = {Other}, author = {Bekins, Barbara A and Spivack, Arthur J and Davis, Earl E and Larry A Mayer} } @article {, title = {Multibeam Bathymetry Mapping for U.S. UNCLOS Concerns: A Gold Mine for Marine Geology}, year = {2007}, month = {Dec 10 - Dec 14}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Law of the Sea}, author = {Andrew A. Armstrong and James V. Gardner and Larry A Mayer} } @article {, title = {High Resolution Mapping of Mines and Ripples at the Martha{\textquoteright}s Vineyard Coastal Observatory}, volume = {32}, year = {2007}, pages = {133-149}, publisher = {IEEE}, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Larry A Mayer and Raymond, Rick and Glang, Gerd and Richardson, M D and Traykovski, P and Arthur Trembanis} } @article {, title = {Geophysical Insights into the Transition Fault Debate: Propagating Strike Slip in Response to Stalling Yakutat Block Subduction in the Gulf of Alaska}, volume = {35}, year = {2007}, pages = {763-766}, publisher = {The Geological Society of America (GSA)}, keywords = {Other}, author = {Gulick, Sean P. and Lowe, Lindsay A and Pavlis, Terry L and James V. Gardner and Larry A Mayer} } @proceedings {, title = {Assessing Bottom Gear Impact in the WGOM Closure Area: A Multifaceted Approach}, year = {2007}, month = {May 10 - May 11}, address = {Durham, NH, USA}, keywords = {Other}, author = {Mashkoor A Malik and Larry A Mayer} } @proceedings {, title = {Acoustic positioning and tracking in Portsmouth Harbour, New Hampshire}, year = {2007}, month = {Sep 29 - Oct 4}, pages = {0-0}, address = {Vancouver, British Columbia, Canada}, keywords = {Other}, author = {Weirathmueller, Michelle and Thomas C Weber and Val Schmidt and McGillicuddy, Glenn and Larry A Mayer and Huff, Lloyd C} } @article {, title = {First Recovery of Submarine Basalts from the Chukchi Borderland and Alpha/Mendeleev Ridge, Arctic Ocean}, volume = {89}, number = {53}, year = {2007}, month = {Dec 10 - Dec 14}, pages = {2123-2124}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Andronikov, A and Mukasa, S B and Larry A Mayer and Brumley, K} } @article {, title = {The Early Miocene Onset of a Ventilated Circulation Regime in the Arctic Ocean}, volume = {447}, year = {2007}, pages = {986-990}, publisher = {Nature Publishing Group}, keywords = {Other}, author = {Martin Jakobsson and Backman, Jan and Rudels, J and Nycander, J and Frank, M and Larry A Mayer and Jokat, W and Sangiorgi, F and O{\textquoteright}Regan, M A and Brinkhuis, H and King, J W and Moran, K} } @article {, title = {Remote estimation of surficial seafloor properties through the application Angular Range Analysis to multibeam sonar data}, volume = {28}, number = {2}, year = {2007}, pages = {119-126}, publisher = {Springer Publisher}, address = {New York, NY, USA}, keywords = {Other}, author = {Fonseca, Luciano and Larry A Mayer} } @proceedings {3166, title = {High Resolution Mapping in support of UNCLOS Article 76: Seeing the seafloor with new eyes}, year = {2007}, month = {May 14 - May 18}, pages = {12-13}, address = {Norfolk, VA, USA}, keywords = {Law of the Sea}, author = {James V. Gardner and Larry A Mayer and Andrew A. Armstrong} } @article {5008, title = {High-resolution mapping in support of UNCLOS Article 76: Seeing the seafloor with new eyes}, year = {2007}, address = {Norfolk, VA}, author = {James V. Gardner}, editor = {Larry A Mayer} } @proceedings {3157, title = {Multibeam Echo Sounding as a Tool for FIsheries Habitat Studies}, year = {2007}, month = {May 21 - May 25}, pages = {1-2}, chapter = {Joint Assembly}, address = {Acapulco, Acapulco, Mexico}, keywords = {Other}, author = {Fonseca, Luciano and Larry A Mayer} } @article {2822, title = {New Iinsights into the Transition Fault Debate: Propagating Strike-slip in Response to Stalled Subduction in the Gulf of Alaska}, volume = {35}, number = {8}, year = {2007}, pages = {763-766}, publisher = {The Geological Society of America (GSA)}, keywords = {Other}, author = {Gulick, Sean P. and Lowe, Lindsay A and Pavlis, Terry L and Larry A Mayer and James V. Gardner} } @article {3876, title = {U.S. Law of the Sea Cruise to Map the Foot of the Slope and 2500-m Isobath of the U.S. Arctic Ocean Margin. Cruise Report for 2007}, year = {2007}, pages = {182}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Law of the Sea}, author = {Larry A Mayer and Andrew A. Armstrong} } @proceedings {, title = {Non-iterative Global Alignment of Image Sequences}, year = {2006}, month = {Aug 14 - Aug 16}, edition = {8th}, chapter = {International Conference on Signal and Image Processing (SIP)}, address = {Honolulu, HI, USA}, keywords = {Other}, author = {Yuri Rzhanov and Larry A Mayer and Beaulieu, S E and Soule, S A and Fornari, D J} } @article {, title = {High Resolution Benthic Mapping Using Multibeam Sonar, Videography, and Sediment Sampling in the Gulf of Maine: Application to Geologic and Fisheries Research.}, volume = {38}, number = {7}, year = {2006}, month = {Nov 5 - Nov 8}, pages = {0-377}, address = {Boston, MA, USA}, keywords = {Multibeam Sonars}, author = {Larry G Ward and Mashkoor A Malik and Randy G Cutter Jr. and Brouder, M A and Raymond E Grizzle and Larry A Mayer and Huff, Lloyd C} } @proceedings {, title = {New Multibeam Mapping of the Gulf of Maine}, year = {2006}, month = {Apr 11 - Apr 11}, chapter = {GIS and Ocean Mapping in Support of Fisheries Research and Managment Conference}, address = {Cambridge, MA, USA}, keywords = {Other}, author = {Andrew A. Armstrong and Larry A Mayer and Case, James D and Fonseca, Luciano} } @article {, title = {Automated generation of geo-referenced mosaics from video collected by deep submergence vehicles: an example from Rosebud vent (Galapagos Rift)}, year = {2006}, pages = {1-1}, edition = {11th}, chapter = {International}, address = {London, London, UK}, keywords = {Other}, author = {Beaulieu, S E and Shank, T M and Soule, S A and Fornari, D J and Yuri Rzhanov and Larry A Mayer} } @proceedings {, title = {Use of Seafloor Electromagnetic and Acoustic Backscatter Data for Seafloor Classification: An Example from Martha{\textquoteright}s Vineyard, Massachusetts}, year = {2006}, month = {Dec 11 - Dec 15}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Evans, R L and Kraft, Barbara J and Larry A Mayer} } @proceedings {, title = {Detection of Bottom Fishing Impacts on Benthic Structure Using Multibeam Sonar, Side Scan Sonar, Video and Interactive 3-D GIS}, year = {2006}, month = {Apr 11 - Apr 11}, chapter = {GIS and Ocean Mapping in Support of Fisheries Research and Managment Conference}, address = {Cambridge, MA, USA}, keywords = {Other}, author = {Mashkoor A Malik and Larry A Mayer} } @article {, title = {Effects of the Western Gulf of Maine Closure Area on Bottom Habitats: A Preliminary GIS-based Assessment}, year = {2006}, month = {Apr 11 - Apr 11}, chapter = {GIS and Ocean Mapping in Support of Fisheries Research and Managment Conference}, address = {Cambridge, MA, USA}, keywords = {Other}, author = {Raymond E Grizzle and Larry G Ward and Larry A Mayer and Cooper, Andrew B and Rosenberg, Andrew A and Brouder, M A and Jennifer K Greene and Abeels, Holly A and Mashkoor A Malik} } @article {, title = {NOAA{\textquoteright}s OKEANOS EXPLORER and Telepresence Technology}, volume = {49}, number = {2}, year = {2006}, pages = {24-33}, publisher = {Maritime Activity Reports, Inc.}, keywords = {Other}, author = {Robert Ballard and Hammond, S and Larry A Mayer} } @proceedings {, title = {Deep Sea Geo-referenced Video Mosaics}, year = {2006}, month = {Sep 18 - Sep 22}, chapter = {Americas}, address = {Boston, MA, USA}, keywords = {Other}, author = {Yuri Rzhanov and Larry A Mayer and Beaulieu, S E and Shank, T M and Soule, S A and Fornari, D J} } @article {, title = {The Alpha-Mendeleev Magmatic Province, Arctic Ocean: A New Synthesis}, year = {2006}, month = {May 26 - May 26}, chapter = {Joint Assembly}, address = {Baltimore, MD, USA}, keywords = {Other}, author = {Vogt, Peter R and Jung, W and Martin Jakobsson and Larry A Mayer and Williamson, M} } @article {, title = {High Resolution Mapping and Backscatter Studies in Support of the Ripples Program}, journal = {Journal of the Acoustical Society of America}, volume = {120}, year = {2006}, pages = {3180-3180}, publisher = {Acoustical Society of America}, address = {Melville, NY, USA}, keywords = {Other}, author = {Kraft, Barbara J and de Moustier, Christian and Brian R Calder and Larry A Mayer} } @article {, title = {Stratigraphic model predictions of Geoacoustic properties}, volume = {31}, number = {2}, year = {2006}, pages = {266-283}, publisher = {IEEE}, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Kraft, Barbara J and Overeem, I and Holland, C W and Pratson, L F and Syvitski, J P and Larry A Mayer} } @article {2791, title = {Mapping Supports Potential Submission to U.N. Law of the Sea}, volume = {87}, number = {16}, year = {2006}, pages = {157-159}, publisher = {American Geophysical Union }, address = {Washington DC, Washington DC, USA}, keywords = {Law of the Sea}, author = {James V. Gardner and Larry A Mayer and Andrew A. Armstrong} } @article {3469, title = {Significant Tectonic and Climatic Events for the Yakutat Block Collision, Gulf of Alaska: Pleistocene Glacial Intensification in the St. Elias Mountains and the Relationship Between the Fairweather and Transition Faults}, year = {2006}, month = {Apr 3 - Apr 7}, pages = {1-2}, address = {Mendoza, Mendoza, Argentina}, keywords = {Other}, author = {Gulick, Sean P. and Willems, Bryce A and Feymueller, J and Powell, Ross D and Jaeger, John M and Kalbas, Jay and Pavlis, Terry L and Lowe, Lindsay A and Larry A Mayer and James V. Gardner} } @article {, title = {On the use of historical bathymetric data to determine changes in bathymetry}, volume = {6}, number = {3}, year = {2005}, pages = {25-41}, publisher = {Geomatics Information \& Trading Center - GITC}, address = {Lemmers, Amsterdam, The Netherlands}, keywords = {Other}, author = {Martin Jakobsson and Andrew A. Armstrong and Brian R Calder and Huff, Lloyd C and Larry A Mayer and Larry G Ward} } @article {, title = {Frontiers in Seafloor Mapping and Visualization}, volume = {27}, number = {1}, year = {2005}, pages = {7-17}, publisher = {Springer Publisher}, address = {New York, NY, USA}, keywords = {Other}, author = {Larry A Mayer} } @article {, title = {Multibeam Bathymetric and Sediment Profiler Evidence for Ice Grounding on the Chukchi Borderland, Arctic Ocean}, volume = {63}, year = {2005}, pages = {150-160}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Other}, author = {Martin Jakobsson and James V. Gardner and Vogt, Peter R and Larry A Mayer and Andrew A. Armstrong and Backman, Jan and Brennan, Rick T and Brian R Calder and John K Hall and Kraft, Barbara J} } @article {, title = {Automated Generation of Geo-referenced Mosaics from Video Data Collected by Deep Submergence Vehicles: Preliminary Results}, year = {2005}, month = {Dec 5 - Dec 9}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Yuri Rzhanov and Larry A Mayer and Beaulieu, S E and Soule, S A and Shank, T M and Fornari, D J} } @article {, title = {High-Resolution Mapping of Mines and Ripples at the Martha{\textquoteright}s Vineyard Coastal Observatory}, volume = {32}, number = {1}, year = {2005}, pages = {133-149}, publisher = {IEEE}, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Larry A Mayer and Raymond, Rick and Glang, Gerd and Richardson, M D and Traykovski, P and Traykovski, P} } @article {, title = {High-resolution Mapping and Backscatter Studies in Support of the Ripples DRI, Ripples DRI Program}, year = {2005}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Other}, author = {Larry A Mayer and de Moustier, Christian and Kraft, Barbara J and Brian R Calder} } @inbook {, title = {Challenges of Collecting Law of the Sea Data in the Arctic: The Arctic and Law of the Sea}, booktitle = {International Energy Policy, the Arctic and the Law of the Sea}, year = {2005}, pages = {125-140}, publisher = {Martinus Nijhoff legacy_publishers}, organization = {Martinus Nijhoff legacy_publishers}, edition = {9}, chapter = {Center for Oceans Law and Policy, 8}, address = {Leiden, South Holland, The Netherlands}, keywords = {Law of the Sea}, author = {Larry A Mayer and Martin Jakobsson and John K Hall} } @article {, title = {Ground-truthing benthic habitat characteristics using video mosaic images: Benthic Habitats and the Effects of Fishing}, volume = {41}, year = {2005}, pages = {171-179}, publisher = {American Fisheries Society}, address = {Bethesda, MD, USA}, keywords = {Seafloor Characterization}, author = {Randy G Cutter Jr. and Yuri Rzhanov and Larry A Mayer and Raymond E Grizzle} } @proceedings {, title = {Insitu Measurement of Sediment Acoustic Properties}, year = {2005}, month = {Jun 28 - Jul 1}, pages = {0-0}, chapter = {Technologies and Results}, address = {Heraklion, Crete, Greece}, keywords = {Other}, author = {Kraft, Barbara J and Ressler, J and Larry A Mayer and Fonseca, Luciano and McGillicuddy, Glenn} } @article {, title = {Seafloor Sounding in Polar and Remote Regions (SSPARR) Project - Initial Field Trials}, year = {2005}, month = {Dec 5 - Dec 9}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Rognstad, M and Anderson, Robert M and Dale N Chayes and Larry A Mayer} } @proceedings {, title = {Northwest Passage Marine Sediments: A Record of Quaternary History and Climate Change}, year = {2005}, month = {Mar 9 - Mar 12}, pages = {0-0}, edition = {35th}, chapter = {Annual}, address = {St. Andrews, New Brunswick, Canada}, keywords = {Other}, author = {Blasco, S M and MacLean, B and Mudie, P and Sonnichsen, G and Bennett, R and Rainey, W and Scott, D and Praeg, D and John E. Hughes Clarke and Barglett, J and Larry A Mayer and Monahan, Dave} } @article {, title = {Mine Burial Experiments at the Martha{\textquoteright}s Vineyard Coastal Observatory}, volume = {32}, year = {2005}, pages = {150-166}, publisher = {IEEE}, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Traykovski, P and Richardson, M D and Larry A Mayer and Irish, James D} } @article {, title = {Measurement of InSitu Acoustic Properties for the ONR Geoclutter Program, Annual Report, Geoclutter Program}, year = {2005}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Other}, author = {Larry A Mayer and Fonseca, Luciano and Kraft, Barbara J} } @article {, title = {A 60 k.y. record of extension across the western boundary of the Basin and Range Province: Estimate of slip-rates from offset shoreline terraces and a catastrophic slide beneath Lake Tahoe}, volume = {33}, number = {5}, year = {2005}, pages = {365-368}, publisher = {The Geological Society of America (GSA)}, keywords = {Other}, author = {Kent, G M and Babcock, J A and Driscoll, Neal W and Harding, A J and Dingler, J A and Seitz, G G and James V. Gardner and Larry A Mayer and Goldman, C R and Heyvaert, A C and Richards, B C and Karlin, R and Morgan, C W and Gayes, P T and Owen, L A} } @article {, title = {Protocols for Calibrating Multibeam Sonar}, volume = {117}, year = {2005}, pages = {2013-2027}, publisher = {Acoustical Society of America}, address = {Melville, NY, USA}, keywords = {Other}, author = {Foote, K G and Chu, D and Hammar, T R and Dr. Ken C Baldwin and Larry A Mayer and Hufnagle Jr., L C and Jech, J M} } @proceedings {, title = {Bottom fishing impacts on benthic structure using multibeam sonar, sidescan and video}, year = {2005}, month = {Mar 29 - Mar 31}, pages = {0-0}, address = {San Diego, CA, USA}, keywords = {Other}, author = {Mashkoor A Malik and Larry A Mayer} } @proceedings {, title = {Seafloor Characterization Through the Application of AVO Analysis to Multibeam Sonar Data}, year = {2005}, month = {Sep 5 - Sep 9}, pages = {0-0}, address = {Bath, UK, UK}, keywords = {Seafloor Characterization}, author = {Fonseca, Luciano and Larry A Mayer and Kraft, Barbara J} } @article {3417, title = {Mapping Near-Surface Gas with Acoustic Remote Sensing Methods, Examples from Eel River Margin, CA and Skjalfandi Bay, Iceland}, year = {2005}, pages = {0-0}, address = {St. Louis, MO, USA}, keywords = {Other}, author = {Fonseca, Luciano and Larry A Mayer} } @article {3864, title = {New Views of the Gulf of Alaska Margin Mapped for UNCLOS Applications}, year = {2005}, pages = {2}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Law of the Sea}, author = {Larry A Mayer and James V. Gardner and Andrew A. Armstrong and Brian R Calder and Mashkoor A Malik and Angwenyi, Clive and Karlipata, Srinivas and Montoro, Hugo and Morishita, Taisei and Mustapha, Abubakar} } @article {3466, title = {New Views of the U.S. Atlantic Margin Mapped for UNCLOS Applications}, volume = {86}, year = {2005}, month = {Dec 5 - Dec 9}, pages = {0-2}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {James V. Gardner and Larry A Mayer and Andrew A. Armstrong and Donaldson, Paul and Infantino, Jason and Davis, Gary and Smith, Debra and Elizabeth Lobecker and Cartwright, Doug and Iwachiw, John and Farr, Stephen and Meadows, Diane and Dorsey, Shirley and Marsh, Gordon and Owen, Wayne} } @proceedings {3092, title = {New Views of the U.S. Continental Margins}, year = {2005}, month = {Mar 29 - Mar 31}, pages = {29-31}, address = {San Diego, CA, USA}, keywords = {Law of the Sea}, author = {James V. Gardner and Larry A Mayer and Andrew A. Armstrong} } @article {3464, title = {Seafloor Sounding in Polar and Remote Regions - A New Instrument for Unattended Bathymetric Observations}, year = {2005}, month = {May 23 - May 27}, pages = {0-2}, address = {New Orleans, LA, USA}, keywords = {Other}, author = {Anderson, Robert M and Chayes, M and Larry A Mayer and Rognstad, M and Val Schmidt} } @article {2779, title = {Shelf-edge Deltas and Drowned Barrier-island Complexes on the Northwest Florida Outer Continental Shelf}, volume = {64}, number = {3}, year = {2005}, pages = {133-166}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Other}, author = {James V. Gardner and Dartnell, Peter and Larry A Mayer and John E. Hughes Clarke and Brian R Calder and Duffy, G} } @article {3860, title = {U.S. Law of the Sea Cruise to Map the Foot of the Slope and 2500-m Isobath of the Gulf of Alaska Continental Margin. Cruise Report}, year = {2005}, month = {October 1}, pages = {111}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Law of the Sea}, author = {James V. Gardner and Larry A Mayer} } @article {2780, title = {U.S. Law of the Sea Mapping}, volume = {9}, year = {2005}, pages = {42-45}, publisher = {Geomatics Information \& Trading Center - GITC}, address = {Lemmers, Amsterdam, The Netherlands}, keywords = {Law of the Sea}, author = {James V. Gardner and Larry A Mayer and Andrew A. Armstrong} } @proceedings {, title = {The Global Ocean Mapping Project (GOMap): Promoting international collaboration for a systematic, high-resolution mapping of the world{\textquoteright}s oceans}, year = {2004}, month = {Aug 24 - Aug 27}, pages = {0-0}, edition = {32nd}, address = {Florence, Florence, Italy}, keywords = {Other}, author = {Cormier, Marie H and de Moustier, Christian and John K Hall and Larry A Mayer and Monahan, Dave and Vogt, Peter R} } @article {, title = {Glacial Advances and Retreats in Tectonic Southeast Alaska During the Little Ice Age and Last Glacial Maximum: Preliminary Results from EW0408}, year = {2004}, month = {Dec 13 - Dec 17}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Gulick, Sean P. and Powell, Ross D and Jaeger, John M and Cowan, E A and Larry A Mayer and Mix, A C and Finney, B P and Pisias, N G and Prahl, F and Stoner, J S} } @article {, title = {Bathymetric Uncertainty Assessment}, year = {2004}, pages = {6}, institution = {Office of Naval Reasearch (ONR) }, address = {DRI}, keywords = {Other}, author = {Larry A Mayer and Brian R Calder} } @inbook {, title = {Evaluating U.S. data holdings relevant to the definition of continental shelf limits}, booktitle = {Legal and Scientific Aspects of Continental Shelf Limits}, year = {2004}, pages = {313-330}, publisher = {Martinus Nijhoff legacy_publishers}, organization = {Martinus Nijhoff legacy_publishers}, edition = {8}, chapter = {Center for Oceans Law and Policy, 8}, address = {Leiden, South Holland, The Netherlands}, keywords = {Other}, author = {Larry A Mayer and Martin Jakobsson and Andrew A. Armstrong} } @proceedings {, title = {Deep-sea image processing}, year = {2004}, month = {Nov 9 - Nov 12}, pages = {647-652}, address = {Kobe, Kobe, Japan}, keywords = {Other}, author = {Yuri Rzhanov and Larry A Mayer and Fornair, D} } @article {, title = {Mosaicking Techniques for Deep Submergence Vehicle Video Imagery - Applications to Ridge2000 Science}, year = {2004}, month = {Dec 13 - Dec 17}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Larry A Mayer and Yuri Rzhanov and Fornari, D J and Soule, S A and Shank, T M and Beaulieu, S E and Schouten, H and Tivey, M} } @article {, title = {Tectonic Details of the Tjornes Fracture Zone, an Onshore-Offshore Ridge-transform in N-Iceland}, year = {2004}, month = {Dec 13 - Dec 17}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Brandsdottir, B and Richter, B and Riedel, C and Dahm, T and Helgadottir, G and Kjartansson, E and Detrick, R S and Magnusson, A and Asgrimmsson, A L and Palsson, B H and Karson, J and S{\textquoteright}mundsson, K and Larry A Mayer and Brian R Calder and Driscoll, Neal W} } @article {, title = {Measurement of In Situ Acoustic Properties for the ONR Geoclutter Program}, year = {2004}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Other}, author = {Larry A Mayer and Kraft, Barbara J and Fonseca, Luciano} } @article {, title = {Estimation and Visualization of Seafloor Uncertainty - Annual Report}, year = {2004}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Other}, author = {Brian R Calder and Kraft, Barbara J and Larry A Mayer} } @article {, title = {Drowned barrier-island complexes and shelf-edge deltas on the northwest Florida outer continental self}, volume = {64}, year = {2004}, pages = {133-166}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Other}, author = {James V. Gardner and Dartnell, Peter and Larry A Mayer and John E. Hughes Clarke and Brian R Calder and Duffy, G} } @article {, title = {High-resolution Holocene Records of Paleoceanographic and Paleoclimatic Variability from the Southern Alaskan Continental Margin}, year = {2004}, month = {Dec 13 - Dec 17}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Finney, B P and Jaeger, John M and Mix, A C and Cowan, E A and Gulick, Sean P. and Larry A Mayer and Pisias, N G and Powell, Ross D and Prahl, F and Stoner, J S} } @article {, title = {Los Angeles and San Diego Margin High-resolution Multibeam Bathymetry and Backscatter Data}, year = {2004}, institution = {U.S. Geological Survey (USGS)}, keywords = {Other}, author = {Dartnell, Peter and James V. Gardner and Larry A Mayer and John E. Hughes Clarke} } @article {3416, title = {AVO Analysis of Multibeam Backscatter, an Example from Little Bay, NH and Skjalfandi Bay, Iceland}, year = {2004}, month = {Dec 13 - Dec 17}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Fonseca, Luciano and Larry A Mayer and Kraft, Barbara J and Brandsdottir, B and Richter, B} } @article {2765, title = {Seabed characterization on the New Jersey middle and outer shelf: Correlability and spatial variably of seafloor sediment properties}, volume = {209}, year = {2004}, pages = {147-172}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Seafloor Characterization}, author = {Goff, John A and Kraft, Barbara J and Larry A Mayer and Schock, Steven G and Sommerfield, Christopher K and Olson, Hilary C and Gulick, Sean P. and Nordfjord, Sylvia} } @article {3853, title = {U.S. Law of the Sea Cruise to Map the Foot of the Slope and 2500-m Isobath of the U.S. Arctic Ocean Margin. Cruise Report for 2004}, year = {2004}, pages = {47}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Law of the Sea}, author = {Larry A Mayer} } @proceedings {, title = {The Integrated Seafloor: Efficient Multi Sensor Processing and Visualization Techniques for Seafloor Mapping Data}, year = {2003}, month = {Nov 23 - Nov 27}, pages = {0-0}, edition = {4th}, chapter = {Australasian Hydrographic Symposium}, address = {Christchurch, Christchurch, New Zealand}, keywords = {Other}, author = {Paton, Mark and Lindsay Gee and Brian R Calder and Larry A Mayer} } @article {, title = {High-resolution Photo-mosaicing of the Rosebud Hydrothermal Vent Site and Surrounding Lava Flows, Galapagos Rift 86W: Techniques and Interpretation}, volume = {84}, number = {46}, year = {2003}, month = {Dec 8 - Dec 12}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Yuri Rzhanov and Larry A Mayer and Fornair, D and Shank, T M and Humphris, S and Scheirer, D and Kinsey, J and Whitcomb, Louis L} } @proceedings {, title = {Electronic Chart of the Future: The Hampton Roads Project}, year = {2003}, month = {Mar 24 - Mar 27}, pages = {0-8}, address = {Biloxi, MS, USA}, keywords = {Other}, author = {Brennan, Rick T and Colin Ware and Alexander, Lee and Andrew A. Armstrong and Larry A Mayer and Huff, Lloyd C and Brian R Calder and Smith, Shep M and Plumlee, Matt D and Roland Arsenault and Glang, Gerd} } @article {, title = {Lost in Iceland? Fracture Zone Complications Along the mid-Atlantic Plate Boundary}, volume = {84}, number = {46}, year = {2003}, month = {Dec 8 - Dec 12}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Brandsdottir, B and Einarsson, P and Detrick, R S and Larry A Mayer and Brian R Calder and Driscoll, Neal W and Richter, B} } @article {, title = {In-situ Measurement of Geoacoustic Sediment Properties: An Example from the ONR Mine Burial Program, Martha{\textquoteright}s Vineyard Coastal Observatory}, volume = {113}, number = {4}, year = {2003}, pages = {0-0}, publisher = {Acoustical Society of America}, address = {Melville, NY, USA}, keywords = {Other}, author = {Kraft, Barbara J and Smith, Shep M and Larry A Mayer and Simpkin, Peter G} } @proceedings {, title = {Seafloor Segmentation Based on Bathymetric Measurements from Multibeam Echosounders Data}, year = {2003}, month = {Jul 1 - Jul 4}, pages = {0-0}, edition = {7th}, address = {Paris, Paris, France}, keywords = {Other}, author = {Yuri Rzhanov and Randy G Cutter Jr. and Larry A Mayer} } @article {, title = {The Tectonic Evolution of the Tjornes Fracture Zone, Offshore Northern Iceland-ridge Jumps and Rift Propagation}, volume = {84}, number = {46}, year = {2003}, month = {Dec 8 - Dec 12}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Detrick, R S and Brandsdottir, B and Driscoll, Neal W and Richter, B and Larry A Mayer and Fornair, D and Brian R Calder and Kent, G M} } @article {, title = {Analysis of Data Relevant to Extending a Coastal State{\textquoteright}s Continental Margin Under Law of the Sea Article 76}, volume = {4}, number = {1}, year = {2003}, pages = {2-18}, publisher = {Geomatics Information \& Trading Center - GITC}, address = {Lemmers, Amsterdam, The Netherlands}, keywords = {Law of the Sea}, author = {Martin Jakobsson and Larry A Mayer and Andrew A. Armstrong} } @proceedings {, title = {Do Quaternary Sediments Register Paleoseismicity or Neotectonic Rejuvenation of Ancient Faults Beneath Lake Ontario?}, year = {2003}, month = {Mar 27 - Mar 29}, pages = {0-0}, edition = {38th Annual Meeting}, chapter = {Northeastern Section}, address = {Halifax, Nova Scotia, Canada}, keywords = {Other}, author = {Lewis, C F and Blasco, S M and Forsyth, D A and Larry A Mayer and Semme J Dijkstra and Jacobi, R D and Todd, B J and Coakley, J P and King, J W} } @proceedings {, title = {New Paradigms for Hydrographic Data Processing and Products}, year = {2003}, month = {Nov 17 - Nov 20}, pages = {0-0}, edition = {3rd}, address = {St. Andrews, New Brunswick, Canada}, keywords = {Other}, author = {Larry A Mayer and Brian R Calder and Brennan, Rick T and Lindsay Gee and Smith, Shep M and Colin Ware and Alexander, Lee and Andrew A. Armstrong and Roland Arsenault and Jurley, M and Moggert, Friedhelm and Plumlee, Matt D and Paton, Mark} } @article {, title = {Bathymetry and Acoustic Backscatter of the Mid and Outer Continental Shelf, Head of De Soto Canyon, Northeastern Gulf of Mexico Data, Images, and GIS}, year = {2003}, institution = {U.S. Geological Survey (USGS)}, keywords = {Other}, author = {Dartnell, Peter and James V. Gardner and John E. Hughes Clarke and Larry A Mayer} } @article {, title = {Automated Segmentation of Seafloor Bathymetry from Multibeam Echosounder Data Using Local Fourier Histogram Texture Features}, volume = {285}, number = {286}, year = {2003}, pages = {355-370}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Other}, author = {Randy G Cutter Jr. and Yuri Rzhanov and Larry A Mayer} } @proceedings {3018, title = {Fusing Information in a 3D Chart of the Future Display}, year = {2003}, month = {Mar 24 - Mar 27}, pages = {0-7}, address = {Biloxi, MS, USA}, keywords = {Other}, author = {Roland Arsenault and Smith, Shep M and Colin Ware and Larry A Mayer and Plumlee, Matt D} } @article {3983, title = {Fusing Information in a 3D Chart-of-the-Future Display}, year = {2003}, month = {March 24-27}, publisher = {The Hydrographic Society of America}, address = {Biloxi, MS}, keywords = {3d chart of the future}, author = {Roland Arsenault and Plumlee, Matt D and Smith, Shep M and Colin Ware and Brennan, Rick T and Larry A Mayer} } @article {2741, title = {Geomorphology acoustic backscatter and processes in Santa Monica Bay from multibeam mapping}, volume = {56}, year = {2003}, pages = {15-46}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Other}, author = {James V. Gardner and Dartnell, Peter and Larry A Mayer and John E. Hughes Clarke} } @article {3457, title = {High-Resolution Multibeam Sonar Survey and Interactive 3-D Exploration of the D-day Wrecks off Normandy}, volume = {84}, number = {46}, year = {2003}, month = {Dec 8 - Dec 12}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Larry A Mayer and Brian R Calder and Schmidt, J S} } @proceedings {3028, title = {Providing the Third Dimension: High-resolution Multibeam Sonar as a Tool for Archaeological Investigations - An Example from the D-day Beaches of Normandy}, year = {2003}, month = {Mar 24 - Mar 27}, pages = {0-16}, address = {Biloxi, MS, USA}, keywords = {D-Day, Other}, author = {Larry A Mayer and Brian R Calder and Schmidt, J S and Malzone, C} } @article {3834, title = {U.S. Law of the Sea Cruise to Map the Foot of the Slope and 2500-m Isobath of the U.S. Arctic Ocean Margin, Barrow to Barrow. Cruise Report}, year = {2003}, pages = {47}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {arctic, ECS, Healy, Law of the Sea, unclos}, author = {Larry A Mayer} } @article {, title = {Bathymetry and Acoustic Backscatter of the Mid and outer continental shelf, head of De Soto Canyon, Northeastern Gulf of Mexico}, year = {2002}, pages = {51}, institution = {U.S. Geological Survey (USGS)}, keywords = {Other}, author = {James V. Gardner and John E. Hughes Clarke and Larry A Mayer and Dartnell, Peter} } @article {, title = {Shallow Water Survey 2001:High Resolution Surveys in Shallow Water}, volume = {34}, number = {4}, year = {2002}, pages = {3-4}, publisher = {Marine Technology Society}, keywords = {Other}, author = {Larry A Mayer and Dr. Ken C Baldwin} } @article {, title = {On the Effect of Random Errors in Gridded Bathymetric Compilations}, volume = {107}, number = {12}, year = {2002}, pages = {1-11}, publisher = {American Geophysical Union }, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Martin Jakobsson and Brian R Calder and Larry A Mayer} } @proceedings {, title = {Sensor-assisted Video Mapping of the Seafloor}, year = {2002}, month = {Oct 29 - Oct 31}, pages = {0-0}, address = {Biloxi, MS, USA}, keywords = {Other}, author = {Yuri Rzhanov and Huff, Lloyd C and Randy G Cutter Jr. and Larry A Mayer} } @article {, title = {Interactive 3-D Visualization: An Important Element in Dealing with Increasing Data Volumes and Decreasing Resources}, volume = {83}, number = {47}, year = {2002}, month = {Dec 6 - Dec 10}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Lindsay Gee and Reed, B and Larry A Mayer} } @proceedings {, title = {Dealing with increasing data volumes and decreasing resources}, year = {2002}, month = {Oct 29 - Oct 31}, pages = {0-21}, address = {Biloxi, MS, USA}, keywords = {Other}, author = {Depner, J and Reed, B and Shannon Byrne and Parker, J and Paton, Mark and Larry A Mayer and Colin Ware} } @article {, title = {On the Estimation of Errors in Sparse Geophysical Datasets}, volume = {107}, number = {12}, year = {2002}, pages = {14-14}, publisher = {American Geophysical Union }, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Martin Jakobsson and Brian R Calder and Larry A Mayer} } @proceedings {, title = {Detection Near-surface Gas with Acoustic Remote Sensing Data}, year = {2002}, month = {Oct 20 - Oct 24}, pages = {0-0}, edition = {8th}, address = {Cartagena, Cartagena, Columbia}, keywords = {Other}, author = {Fonseca, Luciano and Larry A Mayer} } @article {, title = {Site Survey of the Martha{\textquoteright}s Vineyard Coastal Observatory: Backscatter, Grain Size and Temporal Evolution of Rippled Scour Depressions}, volume = {83}, number = {47}, year = {2002}, month = {Dec 6 - Dec 10}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Goff, John A and Larry A Mayer and Schwab, Bill and Traykovski, P and Wilkins, R and Jenkins, Chris and Kraft, Barbara J and Evans, R L and Buynevich, I} } @proceedings {, title = {Application of Wavelet Multi-resolution to Multibeam Backscatter for the Seabed Characterization}, year = {2002}, month = {Mar 5 - Mar 8}, pages = {0-0}, address = {London, London, UK}, keywords = {Seafloor Characterization}, author = {Hou, Tianhang and Larry A Mayer and Yuri Rzhanov} } @article {, title = {The Compilation and Analysis of Data Relevant to a U.S. Claim Under United Nations Law of the Sea Article 76: Maps}, year = {2002}, institution = {U.S. Congress}, keywords = {Law of the Sea}, author = {Martin Jakobsson and Larry A Mayer and Andrew A. Armstrong} } @article {, title = {Bathymetry and Selected Perspective Views Offshore Greater Los Angeles, CA}, year = {2002}, institution = {U.S. Geological Survey (USGS)}, keywords = {Other}, author = {James V. Gardner and Dartnell, Peter and Stone, J C and Larry A Mayer and John E. Hughes Clarke} } @article {, title = {Comparison of In-situ Compressional Wave Speed and Attenuation Measurements to Biot-stoll Model Predictions}, volume = {112}, year = {2002}, pages = {2254-2254}, publisher = {Acoustical Society of America}, address = {Melville, NY, USA}, keywords = {Other}, author = {Kraft, Barbara J and Larry A Mayer and Simpkin, Peter G and Goff, John A} } @article {, title = {Resolving the Ripples (and a Mine): High-Resolution Multibeam Survey of Martha{\textquoteright}s Vineyard ONR Mine Burial Program Field Area}, volume = {83}, number = {47}, year = {2002}, month = {Dec 6 - Dec 10}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Larry A Mayer and Raymond, Rick and Glang, Gerd and Huff, Lloyd C} } @proceedings {, title = {Using MGE Applications and Geomedia in Marine Geophysical/Geological Research}, year = {2002}, month = {Mar 31 - Apr 5}, pages = {0-16}, chapter = {Conference on Human Factors in Computing Systems}, address = {New Orleans, LA, USA}, keywords = {Other}, author = {Martin Jakobsson and Larry A Mayer} } @inbook {, title = {Calculation of in situ acoustic wave properties in marine sediments}, booktitle = {Impact of Littoral Environmental Variability on Acoustic Predictions and Sonar Performance}, year = {2002}, pages = {115-130}, publisher = {Kluwer Press}, organization = {Kluwer Press}, address = {Dordrecht, Dordrecht, The Netherlands}, keywords = {Other}, author = {Kraft, Barbara J and Larry A Mayer and Simpkin, Peter G and P Lavoie and Jabs, E and Goff, John A} } @article {3977, title = {Automated Texture-based Segmentation of Multibeam Sonar Bathymetry Data for Benthic Habitat Mapping in the Piscataqua River, New Hampshire}, year = {2002}, keywords = {Other}, author = {Randy G Cutter Jr. and Yuri Rzhanov and Larry A Mayer} } @article {6562, title = {The Compilation and Analysis of Data Relevant to a U.S. Claim Under United Nations Law of the Sea Article 76: Appendices}, year = {2002}, pages = {98}, institution = {University of New Hampshire}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, author = {Larry A Mayer and Martin Jakobsson and Andrew A. Armstrong} } @article {3821, title = {The Compilation and Analysis of Data Relevant to a U.S. Claim Under United Nations Law of the Sea Article 76: A Preliminary Report}, year = {2002}, pages = {75}, institution = {University of New Hampshire (UNH)}, address = {Center for Coastal and Ocean Mapping (CCOM)/Joint Hydrographic Center (JHC)}, keywords = {Law of the Sea}, author = {Larry A Mayer and Martin Jakobsson and Andrew A. Armstrong} } @article {3980, title = {In Situ Measurement of Geoacoustic Properties: An Example From the ONR Mine Burial Program, Martha{\textquoteright}s Vineyard Coastal Observatory}, year = {2002}, month = {December 6-10}, publisher = {American Geophysical Union }, address = {San Francisco, CA}, keywords = {geoacoustic properties, martha{\textquoteright}s vineyard, mine burial, onr}, url = {http://www.agu.org/meetings/fm02/}, author = {Kraft, Barbara J and Larry A Mayer and Simpkin, Peter G and Goff, John A and Schwab, Bill and Jenkins, Chris} } @article {5004, title = {Morphology, volcanism, and mass wasting in Crater Lake, Oregon}, volume = {114}, year = {2002}, month = {2002}, pages = {675-692}, author = {Bacon, C R and James V. Gardner and Larry A Mayer} } @article {3978, title = {Quantitative Ground-Truthing of Habitat Characteristics Using Video Mosaic Images}, year = {2002}, keywords = {Seafloor Characterization}, author = {Randy G Cutter Jr. and Yuri Rzhanov and Larry A Mayer} } @article {3981, title = {Resolving the Ripples (and a Mine): High-Resolution Multibeam Survey of Martha{\textquoteright}s Vineyard ONR Mine Burial Program Field Area}, year = {2002}, month = {December 6-10}, publisher = {American Geophysical Union }, address = {San Francisco, CA}, keywords = {martha{\textquoteright}s vineyard, mine burial, multibeam survey, onr}, url = {http://www.agu.org/meetings/fm02/}, author = {Larry A Mayer and Raymond, Rick and Glang, Gerd and Huff, Lloyd C} } @article {3414, title = {Seafloor Characterization from Spatial Variation of Multibeam Backscatter vs."Best Estimated" Grazing Angle}, year = {2002}, month = {Dec 6 - Dec 10}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Hou, Tianhang and Larry A Mayer and de Moustier, Christian and Kraft, Barbara J} } @proceedings {, title = {Interactive 3-D Visualization and Exploration of Deepwater Geohazards}, year = {2001}, month = {May 3 - May 6}, pages = {0-11}, address = {Houston, TX, USA}, keywords = {Other}, author = {Larry A Mayer and Fonseca, Luciano and Colin Ware and Paton, Mark and Lindsay Gee and James V. Gardner and Orange, Dan} } @proceedings {, title = {Interactive 3-D Visualization and Analysis of Multi-sensor, Multi-resolution Data Sets}, year = {2001}, month = {Sep 24 - Sep 24}, pages = {0-0}, edition = {2nd}, address = {Portsmouth, NH, USA}, keywords = {Other}, author = {Lindsay Gee and Paton, Mark and Larry A Mayer and James V. Gardner and Depner, J} } @article {, title = {Automated tools for sonar logging on commercial fishing vessels}, volume = {59}, year = {2001}, pages = {226-245}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Other}, author = {Melvin, G and Li, Y and Larry A Mayer and Clay, A} } @article {, title = {The High Frequency Backscattering Angular Response of Gassy Sediments: Model/Data Comparisons from the Eel River Margin, California}, volume = {111}, number = {6}, year = {2001}, pages = {2621-2631}, publisher = {Acoustical Society of America}, address = {Melville, NY, USA}, keywords = {Other}, author = {Fonseca, Luciano and Larry A Mayer and Orange, Dan and Driscoll, Neal W} } @article {, title = {Crater Lake Revealed: Using GIS to Visualize and Analyze Post Caldera Volcanoes Beneath Crater Lake}, volume = {82}, number = {47}, year = {2001}, month = {Dec 10 - Dec 14}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Ramsey, D W and Robinson, J E and Dartnell, Peter and Bacon, C R and James V. Gardner and Larry A Mayer and Buktenica, M} } @proceedings {, title = {Robust Automatic Multi-beam Bathymetric Processing}, year = {2001}, month = {May 21 - May 24}, pages = {0-20}, address = {Norfolk, VA, USA}, keywords = {Other}, author = {Brian R Calder and Larry A Mayer} } @article {, title = {Derivation of del180 from sediment cores log data: Implications for Millennial-scale climate change in the Labordor Sea}, volume = {16}, number = {5}, year = {2001}, pages = {503-514}, publisher = {American Geophysical Union }, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Weber, M E and Larry A Mayer and Hillaire-Marcel, C and Bilodeau, G and Rack, F and Hiscott, R N and Aksu, A E} } @article {, title = {On the Estimation of Errors in Sparse Bathymetric Data Sets}, year = {2001}, pages = {0-31}, publisher = {American Geophysical Union }, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Martin Jakobsson and Brian R Calder and Larry A Mayer} } @inbook {, title = {ArcView Objects in the Fledermaus Interactive 3-D Visualization System: Examples from the STRATAFORM GIS}, booktitle = {Undersea with GIS}, year = {2001}, pages = {23}, publisher = {ESRI Press}, organization = {ESRI Press}, address = {Redlands, CA, USA}, keywords = {Other}, author = {Fonseca, Luciano and Larry A Mayer and Paton, Mark} } @article {, title = {Discovery of an Active Submarine Mud Volcano Along the Nootka Fault West of Vancouver Island}, volume = {82}, number = {47}, year = {2001}, month = {Dec 10 - Dec 14}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Reidel, M and Kelley, D S and Delaney, J R and Spence, G D and Hyndman, R D and Larry A Mayer and Brian R Calder and Lilley, M D and Olson, Hilary C and Schrenk, M O and Coffin, R} } @proceedings {, title = {Seafloor Habitat Mapping: Considering Techniques for Expansion of Spatial Scales}, year = {2001}, month = {Jan 31 - Feb 2}, pages = {0-0}, address = {Bergen, Bergen, Norway}, keywords = {Other}, author = {Randy G Cutter Jr. and Larry A Mayer and Yuri Rzhanov} } @article {, title = {Assessing the {\textquoteright}GEO{\textquoteright} in GEOCLUTTER: New Chirp Sonar, Sampling, and Compressional Wave Veolcity Results from the New Jersey Shelf}, volume = {82}, number = {47}, year = {2001}, month = {Dec 10 - Dec 14}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Austin, J. A. and Goff, John A and Gulick, Sean P. and Fulthorpe, C and Nordfjord, Sylvia and Wiederspahn, M and Saustrup, S and Schock, Steven G and Wulf, J and Gjerding, K and Larry A Mayer and Sommerfield, Christopher K} } @proceedings {, title = {Subtidal Benthic Habitat Mapping Method Development Using Portsmouth Shallow Survey Data}, year = {2001}, month = {Sep 24 - Sep 24}, pages = {0-0}, edition = {2nd}, address = {Portsmouth, NH, USA}, keywords = {Other}, author = {Randy G Cutter Jr. and Larry A Mayer and Yuri Rzhanov} } @article {, title = {Automatic Processing of High-rate, High-density Multibeam Echosounder Data}, volume = {4}, year = {2001}, pages = {0-24}, publisher = {American Geophysical Union }, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Brian R Calder and Larry A Mayer} } @article {, title = {3-D visualization for pelagic fisheries assessment and research}, volume = {59}, year = {2001}, pages = {216-225}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Other}, author = {Larry A Mayer and Li, Y and Melvin, G} } @article {, title = {Enhanced Acoustic Reflectivity Due to High Abundance of Sand Dollars, Dendraster excentricus}, volume = {19}, year = {2001}, pages = {135-145}, publisher = {Taylor \& Francis}, keywords = {Other}, author = {Fenstermacher, L E and Crawford, G B and Borgeld, J C and Britt, T and George, M and Klien, A and Driscoll, Neal W and Larry A Mayer} } @proceedings {, title = {Interactive 3D visualization and analysis of multi-sensor, multi-relolution data sets}, year = {2001}, month = {Sep 24 - Sep 24}, edition = {2nd}, address = {Portsmouth, NH, USA}, keywords = {Data Visualization}, author = {Lindsay Gee and Paton, Mark and Larry A Mayer and Colin Ware and James V. Gardner and Depner, J} } @article {, title = {Differential Strain Accumulation Across Lake Tahoe as Measured From Submerged Paleo-shorelines}, volume = {82}, number = {47}, year = {2001}, month = {Dec 10 - Dec 14}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Dingler, J A and Kent, G M and Babcock, J A and Driscoll, Neal W and Harding, A J and Seitz, G G and James V. Gardner and Goldman, C R and Larry A Mayer and Morgan, C W and Richards, B C} } @proceedings {2972, title = {Comparing Historical and Contemporary Hydrographic Data Sets: An Example from Great Bay, New Hampshire}, year = {2001}, month = {Sep 24 - Sep 24}, pages = {0-0}, edition = {2nd}, address = {Portsmouth, NH, USA}, keywords = {Great Bay, Other}, author = {Martin Jakobsson and Andrew A. Armstrong and Brian R Calder and Larry A Mayer} } @proceedings {2974, title = {Error Estimation of Bathymetric Grid Models Derived from Historic and Contemporary Data Sets}, year = {2001}, month = {May 21 - May 24}, pages = {0-17}, address = {Norfolk, VA, USA}, keywords = {Other}, author = {Martin Jakobsson and Brian R Calder and Larry A Mayer and Andrew A. Armstrong} } @article {3972, title = {On the Estimation of Errors in Gridded Bathymetric Compilations}, year = {2001}, month = {December 10-14}, publisher = {American Geophysical Union }, address = {San Francisco, CA}, keywords = {estimation of errors, gridded bathymetric compilations}, author = {Martin Jakobsson and Brian R Calder and Larry A Mayer and Andrew A. Armstrong} } @article {3439, title = {On the Estimation of Errors in Sparse Bathymetric Geophysical Data Sets}, volume = {82}, number = {20}, year = {2001}, month = {May 29 - Jun 2}, pages = {0-0}, chapter = {Spring Meeting}, address = {Boston, MA, USA}, keywords = {Other}, author = {Martin Jakobsson and Brian R Calder and Larry A Mayer and Andrew A. Armstrong} } @proceedings {2980, title = {GeoZui3D: Data Fusion for Interpreting Oceanographic Data}, year = {2001}, month = {Nov 5 - Nov 8}, pages = {2498-2502}, address = {Honolulu, HI, USA}, keywords = {GeoZui4D}, author = {Colin Ware and Plumlee, Matt D and Roland Arsenault and Larry A Mayer and Smith, Shep M and House, Don H} } @article {3974, title = {Martha{\textquoteright}s Vineyard Survey: Data collected by Bill Schwab and Bill Danforth - USGS}, year = {2001}, keywords = {Other}, author = {Larry A Mayer} } @article {3406, title = {Seafloor Characterization from Spatial Variation of Multibeam Backscatter vs. Grazing Angle}, volume = {83}, number = {47}, year = {2001}, month = {Dec 10 - Dec 14}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Seafloor Characterization}, author = {Hou, Tianhang and Huff, Lloyd C and Yuri Rzhanov and Larry A Mayer} } @article {3405, title = {The STRATAFORM GIS: Interactive Exploration in 2 and 3 Dimensions}, volume = {82}, number = {47}, year = {2001}, month = {Dec 10 - Dec 14}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Larry A Mayer and Fonseca, Luciano and Paton, Mark and McLeod, Pam and Martin Jakobsson} } @article {3971, title = {Surficial Backscatter of the Eel River Margin: IT{\textquoteright}S JUST GAS!}, year = {2001}, keywords = {Other}, author = {Fonseca, Luciano and Larry A Mayer and Yun, Janet and Driscoll, Neal W and Orange, Dan} } @article {, title = {The Development of Chirp Sonar Technology and Its Applications}, volume = {81}, number = {48}, year = {2000}, month = {Dec 15 - Dec 19}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Schock, Steven G and LeBlanc, L R and Larry A Mayer} } @article {, title = {Modeling High-Frequency Seafloor Backscattering of Gassy Sediments: The Eel River Margin Case}, volume = {81}, number = {48}, year = {2000}, month = {Dec 15 - Dec 19}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Fonseca, Luciano and Larry A Mayer} } @proceedings {, title = {Interactive 3-D Visualization: A tool for seafloor navigation, exploration, and engineering}, year = {2000}, month = {Sep 11 - Sep 14}, pages = {913-920}, address = {Providence, RI, USA}, keywords = {Other}, author = {Larry A Mayer and Pato, C W and Lindsay Gee and James V. Gardner and Colin Ware} } @article {, title = {Multibeam sonar backscatter lineaments and anthropogenic organi components in lacustrine silty clay, evidence of shipping in western Lake Ontario}, volume = {43}, year = {2000}, pages = {307-324}, publisher = {Elsevier}, address = {New York, NY, USA}, keywords = {Other}, author = {Lewis, C F and Larry A Mayer and Mukhopadhyay, P K and Kruge, M A and Coakley, J P and Smith, D M} } @article {, title = {Physical Properties and Their Relation to High Frequency Climate Change as Recoded by IMAGES Cores From the Labrador Sea}, volume = {81}, number = {48}, year = {2000}, month = {Dec 15 - Dec 19}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Weber, M E and Larry A Mayer and Hillaire-Marcel, C} } @article {, title = {High-resolution Multibeam Mapping of Crater Lake, Oregon}, volume = {81}, number = {48}, year = {2000}, month = {Dec 15 - Dec 19}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {James V. Gardner and Larry A Mayer and Buktenica, M and Bacon, C R and Dartnell, Peter and Hellequin, L and Ramsey, D W and Robinson, J E} } @article {, title = {Statistical Processing of Multibeam Sonar Data from SAX-99}, volume = {81}, number = {48}, year = {2000}, month = {Dec 15 - Dec 19}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Brian R Calder and Yuri Rzhanov and Fonseca, Luciano and Larry A Mayer and Flood, R D} } @article {, title = {TracEd: A Remote Acoustic Seafloor Characterization System for Use with Vertical Incidence Echosounders}, year = {2000}, pages = {1211-1217}, publisher = {IEEE}, address = {Washington DC, Washington DC, USA}, keywords = {Seafloor Characterization}, author = {Semme J Dijkstra and Larry A Mayer} } @article {, title = {Joe Kravitz and the Chirp Sonar: The Vision of a Prophet, the Patience of a Saint}, volume = {81}, number = {48}, year = {2000}, month = {Dec 15 - Dec 19}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Larry A Mayer and LeBlanc, L R and Schock, Steven G} } @article {, title = {Multibeam Bathymetry and Backscatter at 300 kHz in the SAX99 Study Area, West Florida Shelf}, volume = {81}, number = {48}, year = {2000}, month = {Dec 15 - Dec 19}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Flood, R D and Vicki L Ferrini and Larry A Mayer} } @article {, title = {Morphology and processes in Lake Tahoe (California-Nevada)}, volume = {112}, number = {5}, year = {2000}, pages = {736-746}, publisher = {The Geological Society of America (GSA)}, keywords = {Other}, author = {James V. Gardner and Larry A Mayer and John E. Hughes Clarke} } @article {3969, title = {Modeling High-Frequency Seafloor Backscattering of Gassy Sediments: The Eel River Margin Case}, year = {2000}, keywords = {Other}, author = {Fonseca, Luciano and Larry A Mayer} } @article {2703, title = {The NOAA Joint Hydrographic Center and the UNH Center for Coastal and Ocean Mapping: An Educational and Research Partnership of the Federal Government}, volume = {1}, year = {2000}, pages = {705-710}, publisher = {IEEE}, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Andrew A. Armstrong and Larry A Mayer} } @proceedings {, title = {The STRATAFORM GIS}, year = {1999}, pages = {0-0}, address = {St. Andrews, New Brunswick, Canada}, keywords = {Other}, author = {Larry A Mayer and Fonseca, Luciano and Pacheco, M and Galway, S and Martinez, J and Hou, Tianhang} } @proceedings {2955, title = {Data handling methods and target detection results for multibeam and sidescan data collected as part of the search for SwissAir Flight 111}, year = {1999}, month = {Oct 20 - Oct 23}, pages = {0-11}, edition = {1st}, chapter = {International}, address = {St. Andrews, New Brunswick, Canada}, keywords = {Other}, author = {John E. Hughes Clarke and Larry A Mayer and Shaw, J and Parrott, R and Lamplugh, Mike and Bradford, J} } @article {5002, title = {High-resolution multibeam bathymetry of East and West Flower Gardens and Stetson Banks, Gulf of Mexico}, volume = {16}, year = {1999}, month = {19998}, pages = {131-143}, author = {James V. Gardner}, editor = {Larry A Mayer} } @proceedings {2954, title = {Mapping a Continental Shelf and Slope in the 1990s: A Tale of Three Multibeams}, year = {1999}, month = {Oct 20 - Oct 23}, pages = {0-11}, edition = {1st}, chapter = {International}, address = {Sydney, Australia}, keywords = {Other}, author = {James V. Gardner and John E. Hughes Clarke and Larry A Mayer and Kleiner, A and Paton, Mark} } @inbook {5003, title = {Using multibeam sonar surveys for submarine landslide investigations}, booktitle = {Slope Stability Engineering}, year = {1999}, month = {05/1999}, pages = {127-134}, publisher = {Balkema}, organization = {Balkema}, author = {Locat, J and James V. Gardner and Lee, H J and Larry A Mayer and John E. Hughes Clarke} } @proceedings {, title = {High Resolution Side-Scan and Seismic Images of Landslides on the Northern California Continental Shelf}, year = {1998}, pages = {0-0}, chapter = {Fall Meeting}, address = {San Francisco, CA, USA}, keywords = {Other}, author = {Driscoll, Neal W and Orange, Dan and Fonseca, Luciano and Larry A Mayer} } @article {2690, title = {The limits of spatial resolution achievable using a 30kHz multibeam sonar: model predictions and field results}, volume = {3}, year = {1998}, pages = {1823-1827}, publisher = {IEEE}, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {John E. Hughes Clarke and James V. Gardner and Torresan, M and Larry A Mayer} } @proceedings {, title = {Interactive 3-D Tools for Pipeline Route Planning}, volume = {2}, year = {1997}, month = {Oct 6 - Oct 9}, pages = {1216-1222}, address = {Halifax, Nova Scotia, Canada}, keywords = {Other}, author = {Paton, Mark and Larry A Mayer and Colin Ware} } @proceedings {2927, title = {A multi-faceted acoustic ground-truthing experiment in the Bay of Fundy}, volume = {15}, number = {2}, year = {1993}, month = {Oct 24 - Oct 28}, pages = {203-220}, address = {Bath, UK, UK}, keywords = {Other}, author = {Larry A Mayer and John E. Hughes Clarke and David E Wells and Colin Ware} } @article {, title = {Downhole logging as a paeoceanographic tool on ocean drilling program leg 138: Interface between high-resolution stratigraphy and regional syntheses}, volume = {7}, number = {6}, year = {1992}, pages = {691-700}, publisher = {American Geophysical Union }, address = {Washington DC, Washington DC, USA}, keywords = {Other}, author = {Lyle, Mitchell and Larry A Mayer and Pisias, Micklas and Hagelburg, Terri and Dadey, Kathy and Bloomer, Stephen and the Shipboard Scientific Party of Leg 138,} } @proceedings {, title = {3-d visualization of evolutionary spectra of Leg 138 carbonate records}, year = {1992}, month = {Sep 1 - Sep 5}, pages = {192-193}, chapter = {4th}, address = {Kiel, Schleswig-Holstein, Germany}, keywords = {Data Visualization}, author = {Larry A Mayer and Shackleton, N J and Hagelburg, Terri and Pisias, N G and Colin Ware and Marinelli, K} }