Comparison of Geomorphology and Benthic Habitat Type Along Two Ridge Scarps on the Central and Outer Blake Plateau, Southeast US Continental Margin

Windows to the Deep 2018 and 2019, two seafloor mapping and exploration missions, were recently conducted by the National Oceanic Atmospheric Administration’s Office of Ocean Exploration and Research (NOAA OER) to collect pertinent information about uncharted and poorly understood deep-water areas off the southeast coast of the United States. Expeditions EX1806 and EX1903 implemented the use of high-resolution multibeam sonar mapping and remotely operated vehicle (ROV) Deep Discoverer dives, and included exploring bioherms, ridge scarps, and other benthic habitat types across the broad continental slope known as the Blake Plateau. Deep Discoverer ROV dives EX1806-04 and EX1903-08 were conducted on two ridge scarp features, between 830 and 1,110 m depth along the outer and central portions of the Blake Plateau, respectively, east of the Gulf Stream’s main access. Multibeam sonar data were used to generate high resolution bathymetry, slope, and backscatter intensity surfaces at the dive sites, to investigate the geomorphology of each area, and video footage was analyzed for benthic taxa abundance and diversity. These dives encountered an abundance of marine life, including species of coral yet to be described, with higher concentrations of biota observed at the top ledge of the scarp features. Geomorphologic and benthic habitat results from these two ridge scarp areas will be compared.