Recent Discovery of Cold Seep Communities near Baltimore and Norfolk canyons off the US Middle Atlantic Coast

Although chemosynthetic communities associated with methane cold seeps are well known from a variety of locations, such small scale ecosystems appear to be relatively rare along the US and Canadian Atlantic slope. As part of an interdisciplinary exploration of mid-Atlantic canyons (August - September 2012), we “re-discovered” a large cold seep community along the flank of Baltimore Canyon. This seep had been briefly photographed by camera sled over 30 years ago, but its position and size were not well documented. We described habitats and fauna at this seep during three ROV dives, resulting in about 25 hours of video and numerous collections. Data so far indicate the seep is contained in an area of about 1 km2 on a gently sloping sandy bottom in a depth range of about 390-430 m. Patches of living and dead mussels, Bathymodiolus childressi, carpet the bottom densely in places. Active putative methane bubbling was commonly observed as were white bacterial mats and what appears to be authigenic carbonate rocks. Deep-sea corals and a variety of fishes and other invertebrates were associated with the seep generated habitats (e.g., mussel beds, carbonate rocks). Since the nearest known population of B. childressi is in the north-central Gulf of Mexico, this discovery is significant in terms of mussel distribution and seep community ecology. Additional data will be collected from this seep during a May 2013 cruise, and a potential new, much deeper seep (indicated from multibeam sonar mapping) near Norfolk Canyon will be explored. These data will be presented but were not available for this abstract.

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First Name: 
Sandra
Last Name: 
Brooke
Telephone: 
425-449-1344
Affiliation: 
Florida State University
First Name: 
Steve
Last Name: 
Ross
Affiliation: 
University of North Carolina at Wilmington
Choose keywords that are most applicable to your abstract. (Three maximum.): 
Biogeography
Distribution and abundance
Ecological Interactions
Abstract ID: 
CBE5-167