@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 {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 {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} }