Recent exploration efforts on of the Southeastern US continental margin reveal extensive connected and isolated cold-water coral mounds in areas beyond predictive models

A cold-water scleractinian coral (CWC), Lophelia pertusa, acts as the foundation for deep-sea ecosystems by contributing to nutrient and carbon cycling and providing biogenic habitats, feeding grounds, and nurseries for many fishes and invertebrates. While the presence of L. pertusa colonies along the Southeastern US (SEUS) continental margin has been known for decades, recent expeditions have documented their broad distribution and dynamic nature. Much of the continental margin still lacks bathymetric data and even less of the region has been directly observed. During 2018-2019, there were extensive efforts to map and explore the habitats and offshore resources of the SEUS continental margin by NOAA’s Office of Ocean Exploration and Research (OER) and the BOEM-USGS-NOAA interagency project, Deep Sea Exploration to Advance Research on Coral, Canyon, and Cold seep Habitats (DEEPSEARCH), as part of the Atlantic Seafloor Partnership for Integrated Research and Exploration (ASPIRE) campaign. Through these efforts, significant portions of the continental margin, including the extensive Blake Plateau, were mapped for the first time and revealed a number of knoll or mound features. The topography, isolation, and eastward location of these features made them a target for Remotely Operated Vehicle (ROV) exploration during the EX1903 L2 expedition. ROV operations revealed thriving L. pertusa mounds and confirmed that these features were likely created by the accumulation of L. pertusa skeleton over time. The data generated during these expeditions is contributing to refining and optimizing habitat suitability models for CWCs; the rugged topography revealed in new mapping efforts drives suitable L. pertusa habitat where previous models using coarser-resolution bathymetry had placed a low probability of scleractinians. Notably, this includes parts of the Blake Plateau eastward of any previously known L. pertusa presence. These exploratory efforts are continuing to add to the knowledge base of where CWC mounds thrive in the Atlantic basin, likely contributing to ecosystems services at a magnitude we are just starting to understand.