Monterey Bay Aquarium Research Institute

Jeffrey Baguley, Ph.D.

Department of Biology
University of Nevada

Deep-sea benthos response to the Deepwater Horizon oil spill

Wednesday — August 8, 2012
Pacific Forum — 3:00 p.m.

It is apparent that oil from the Deepwater Horizon blowout reached the bottom of the Gulf of Mexico leading to the question: were deep-sea benthos affected? Deep-sea soft-sediment cores were taken at 169 stations during September–October 2010 response cruises aboard the R/V Gyre and R/V Ocean Veritas to measure impacts on macrofauna and meiofauna; the two main soft-bottom benthic invertebrate groups. Benthic community response with particular focus on the meiobenthos will be discussed here.

Community structure in relation to chemical loads was analyzed with exploratory multivariate analysis. Altered abundance and diversity were found at stations closest to the wellhead and at greater distances towards the southwest. Effects were correlated to PAH, total petroleum hydrocarbon (TPH), and barium concentrations, distance to the wellhead, but not distance to known hydrocarbon seeps. Meiobenthic response at impacted stations was characterized by reductions in diversity, increased nematode:harpacticoid ratios, and increased nematode abundance relative to background conditions. Based on our current knowledge of deep-sea biology and benthic community succession following previous oil spills, recovery rates are likely to be slow, on the order of decades or longer.


Next: August 15—MBARI Summer Intern Symposium, All day event