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Edited by Charles H. Peterson, University of North Carolina at Chapel Hill, Morehead City, NC, and accepted by the Editorial Board June 27, 2014 (received for review February 25, 2014)
Significance
The Deepwater Horizon blowout released more oil and gas into the deep sea than any previous spill. Soon after the well was capped, a deep-sea community 13 km southwest of the wellhead was discovered with corals that had been damaged by the spill. Here we show this was not an isolated incident; at least two other coral communities were also impacted by the spill. One was almost twice as far from the wellhead and in 50% deeper water, considerably expanding the known area of impact. In addition, two of four other newly discovered coral communities in the region were fouled with commercial fishing line, indicating a large cumulative effect of anthropogenic activities on the corals of the deep Gulf of Mexico.
Abstract
On April 20, 2010, the Deepwater Horizon (DWH) blowout occurred, releasing more oil than any accidental spill in history. Oil release continued for 87 d and much of the oil and gas remained in, or returned to, the deep sea. A coral community significantly impacted by the spill was discovered in late 2010 at 1,370 m depth. Here we describe the discovery of five previously unknown coral communities near the Macondo wellhead and show that at least two additional coral communities were impacted by the spill. Although the oil-containing flocullent material that was present on corals when the first impacted community was discovered was largely gone, a characteristic patchy covering of hydrozoans on dead portions of the skeleton allowed recognition of impacted colonies at the more recently discovered sites. One of these communities was 6 km south of the Macondo wellhead and over 90% of the corals present showed the characteristic signs of recent impact. The other community, 22 km southeast of the wellhead between 1,850 and 1,950 m depth, was more lightly impacted. However, the discovery of this site considerably extends the distance from Macondo and depth range of significant impact to benthic macrofaunal communities. We also show that most known deep-water coral communities in the Gulf of Mexico do not appear to have been acutely impacted by the spill, although two of the newly discovered communities near the wellhead apparently not impacted by the spill have been impacted by deep-sea fishing operations.
Footnotes
- ↵1To whom correspondence should be addressed. Email: cfisher{at}psu.edu.
Author contributions: C.R.F., C.L.K., D.R.Y., H.H.R., W.W.S., E.E.C., and T.M.S. designed research; C.R.F., P.-Y.H., C.L.K., D.R.Y., W.W.S., E.E.C., T.M.S., S.P.B., M.G.S., E.A.L., and J.M.B. performed research; C.R.F., P.-Y.H., C.L.K., D.R.Y., S.P.B., M.G.S., and E.A.L. analyzed data; and C.R.F. wrote the paper.
Conflict of interest statement: The cruises and some of the analyses were funded by National Oceanic and Atmospheric Administration and BP as part of the Deepwater Horizon (DWH) oil spill Natural Resource Damage Assessment (NRDA). Neither the DWH NRDA Trustees nor BP had a role in sample processing, data analysis, decision to publish, or preparation of the manuscript. Preapproval to submit the manuscript for publication was provided by representatives of the NRDA Trustees and independently by the Bureau of Ocean Energy Management (BOEM). W.W.S. is an employee of BOEM.
This article is a PNAS Direct Submission. C.H.P. is a guest editor invited by the Editorial Board.
Data deposition: The coral image dataset has been deposited at Penn State ScholarSphere, https://scholarsphere.psu.edu/collections/pv63g1177 (Gulf of Mexico Research Initiative GRIDC#R1.x132.136:0020).
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1403492111/-/DCSupplemental.
Footprint of Macondo Well blowout to deep corals
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