Megafaunal Benthic Ecology of the Submarine Canyons of Southern California

Submarine canyons have been studied to a very limited extent in spite of their important biological roles as hotspots of secondary production and organic matter conduits between the shelf and the deep sea. The heterogeneity and rugged terrain of submarine canyons makes them difficult to sample using traditional means such as trawling, however there has be a great deal of success in using ROVs to study these important yet poorly understood environments. A number of ROV dives were executed within the submarine canyons of Southern California during research expeditions in 2005 and 2010. Although these dives were planned and executed with geological research in mind, the video data obtained during these dives can be utilised for ecological research. Video transects from a range of depths in five submarine canyons have been analysed to produce presence/absence data for each site and a comparison of benthic communities in differing depths, locales, and canyons has been performed. No difference was found between canyons based on canyon activity however there was a significant trend for community composition to vary between water depths. This depth-related trend is in agreement with the findings of previous studies and is most probably tied to the depth ranges of the various organisms studied, which is dictated by their tolerances of depth depth-correlated variables such as temperature, salinity and oxygen concentration.