Classifying Interrelationships Between Deep-Sea Coral and Local Geomorphology on a Blake Escarpment Intraslope Terrace, Southeast U.S. Continental Margin

Hayley Caitlin Drennon, College of Charleston, Charleston, United States and Leslie Sautter, College of Charleston, Geology and Environmental Geosciences, Charleston, SC, United States
Abstract:
From May 22 through July 2, 2018, NOAA and partners, aboard the NOAA Ship Okeanos Explorer conducted a telepresence enabled ocean exploration expedition, Windows to the Deep 2018, on the Southeast U.S. Continental Margin to collect baseline information about understudied or unknown deep-water habitats. Video footage collected during EX1806 Dive 04 along a steeply terraced section of the Blake Escarpment, referred to as an intraslope terrace, revealed over 25 different deep-sea coral genera, living within a variety of associated habitats. Intraslope terraces are characterized by flat-lying strata with outcropping edges that result in a stair-step like slope. Active benthic communities thrive in geologic environments with high slope and high backscatter intensity, features often described in association with intraslope terraces. Utilizing video footage of observed deep-sea coral, a semi-quantitative study was conducted of genera abundance as it relates to observed substrate character. Diversity and abundance of genera were compared to the substrate’s backscatter intensity along the ROV dive track. Results were summarized through projection of approximate location onto visualizations depicting bathymetry and backscatter, revealing a pattern of varying biota diversity and frequency according to geologic environment.