The Deepwater Horizon oil spill (DWHOS) was unique not only for its volume, but also for its depth of influence (0-1500 m). Variable amounts of hydrocarbons reached the ocean surface and/or seafloor, whereas 100% went through the water column. Understanding this pelagic habitat is important. For example, about half of all fish species that occur in the Gulf of Mexico (GoM) spend all or part of their lives in the open ocean. Many mesopelagic and bathypelagic species migrate vertically each night to feed in the upper water column and return to deep water during the day. This behavior promotes rapid cycling of natural and anthropogenic material in the water column. Deep-pelagic nekton are prey for gamefishes, seabirds, and marine mammals. Given the steady growth of oil exploration and operations, the likelihood of future spills emphasizes the need to document acute and chronic effects on the pelagic fauna. The GoMRI-funded DEEPEND (Deep-Pelagic Nekton Dynamics) consortium was created for that purpose. DEEPEND is in the second of a 3year program that builds on two intensive NOAA-supported surveys during 2010-11. DEEPEND is focussed on timescales from short-term to interannual to appraise the dynamic nature of communities using a suite of integrated approaches. These investigations include: 1) a direct assessment of GoM deep-pelagic community structure including the physical and biological drivers of this structure; 2) a time-series analysis/comparison of biophysical data; 3) a time-series examination of differences in genetic diversity among key species; and 4) a biogeochemical analysis of the effect of DWHOS on pelagic biota.
Available at: http://works.bepress.com/mahmood-shivji/117/