Macrobenthic community structure in the deep Gulf of Mexico one year after the Deepwater Horizon blowout

The impacts of the 2010 Deepwater Horizon (DWH) disaster on deep-sea Gulf of Mexico benthic communities were analyzed one year after the blowout. Richness, diversity, and evenness were severely impaired within a radius of approximately 1 km around the DWH wellhead. However, lower diversity than background was observed in several stations up to 29 km to the southwest of the wellhead. Compared to samples from 2010, abundance near the DWH wellhead increased in 2011 with some of the highest values found at stations within the 1 km radius. The increase was mostly caused by the high abundance of opportunistic polychaetes of the family Dorvilleidae, genus Ophryotrocha. At contaminated stations near the DWH wellhead, diversity did not change with increased sampling area, whereas a steep increase of diversity with increasing sampling area was observed at stations farther from the wellhead. The spatial extent of DWH impacts appeared to decrease from 2010 to 2011. Impacts on diversity near the wellhead were still observed; however, the large increase in abundance may indicate the initial stages of recovery, year-to-year variability, or an early stage of succession following a disturbance; and this can be resolved only with additional temporal sampling.