RAPID: Collaborative Research: Acute response of benthic hardbottom communities to oil exposure in the deep Gulf of Mexico

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Over the past 20 years of work in the deep Gulf of Mexico we have assembled a large database on over 40 sites with chemosynthetic communities and 14 natural sites with extensive cold-water coral development. As a result of the ongoing oil leak at the Deep Water Horizon rig, some of these sites are very likely to be exposed to high concentrations of hydrocarbons and dispersant. Visitation, imaging, and sampling in the very near future at a subset of these sites will provide timely information on any acute impacts on benthic fauna, as well as provide ground-truthing of data suggesting that the oil/dispersant mixture is spreading along density gradients at depth.We propose to revisit sites where we have ongoing studies, including pre-exposure tissue and live coral samples, and well-marked and navigated mosaics of coral and coral/tubeworm communities. A site in MMS lease block VK 826 and another in MC 751 are identified as high-priority sites with extant mosaics, excellent pre-existing macrofauna sample sets, and are currently monitored with time series sediment traps. A third high-priority site is in MMS lease Block MC 294, within 7 miles of the leak site. This site harbors a typical seep community of mussels and tubeworms. Numerous others could be visited if ongoing plume modeling and ground-truthing work suggests other important areas or depths in the Gulf of Mexico for study.At each site visited, we will conduct high resolution imaging of the hard ground megafaunal communities for comparisons to similar imagery collected last year and make a series of macrofauna collections for a suite of analyses. These analyses will include analysis of hydrocarbon load (tissue PAHs), Comet assays to assess DNA damage, analysis of phospholipids fatty acid biomarkers from bacteria in coral mucous, and also experiments with living Lophelia pertusa for growth studies under laboratory conditions.Broader ImpactsFor the first time in US history, we are dealing with a massive leakage and spread of oil and trial dispersants (potentially much more toxic to life than the oil itself), which have been directly injected at over 1500m into the deep sea. The scale of this disaster dwarfs any previous oil spills and how plumes of these substances will travel in the deep sea and what their effects on the benthos will be is still almost completely unknown. As a result, there is a critical need to assess the impact on deep-sea megafauna communities and communicate those results as soon as possible.