Exploring the Interactions between Geologic and Biologic Processes in the Poorly Known Submarine Canyons Off Cape Hatteras, U.S. Atlantic Margin

Jason D Chaytor1, Amanda W Demopoulos2, Martha S Nizinski3, Brian D Andrews1, Ryan Gasbarro4 and Erik E Cordes4, (1)USGS Coastal and Marine Science Center Woods Hole, Woods Hole, MA, United States, (2)US Geological Survey, Wetland and Aquatic Research Center, Gainesville, FL, United States, (3)NOAA, NMFS, National Systematics Laboratory, Washington, DC, United States, (4)Temple University, Philadelphia, PA, United States
Abstract:
The continental margin offshore of Cape Hatteras lacks the morphologically complex, deeply incised, shelf-indenting submarine canyons present along the continental slope off the northern- and Mid-Atlantic U.S. Instead, several factors influence the creation and maintenance of a unique set of submarine canyons in the Hatteras region, including: the presence of a narrow shelf, a steep and narrow upper slope, powerful surface and bottom currents, variations in the underlying continental margin construction and recent geologic processes. Yet this region has remained largely unexplored over the last 30 years. Recent exploration and assessment activities (e.g., Atlantic Seafloor Partnership for Integrated Research and Exploration, DEEP Sea Exploration to Advance Research on Coral/Canyon/Cold seep Habitats project and the NOAA Deep Sea Coral Research and Technology Program) in the region have provided unprecedented access to Pamlico, Hatteras and adjacent canyons, through the use of ship-based mapping and sampling tools, as well as seafloor observation and sampling using remotely-operated, autonomous and human-occupied platforms. Sediments are actively transported within the axes, with hurricane-driven sediment input at the heads of these canyons a potential major source. Wall modification is ongoing via physical erosion and biological activity at these canyon margins. We will evaluate the mechanisms responsible for development of these little-known canyons by examining canyon geomorphology, sediment characteristics, wall lithology, outcrop structure, the distribution, abundance, and health of benthic communities, and physical oceanographic processes. A particular focus of this work is the evaluation of benthic community response to major disturbance events within the canyons, such as sediment gravity flows and wall collapse, and how these observations can be used to evaluate the stability of canyon walls and the rates at which canyon evolve.