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| Earth on Oct 08, 2013

Recovery of deep sea life after Gulf oil spill may take decades

A new study of deep sea life after the 2010 Deepwater Horizon oil spill in the Gulf of Mexico has found far-ranging impacts that may take decades to reverse.

One of the first studies to evaluate deep sea life after the April 20, 2010 Deepwater Horizon oil spill in the Gulf of Mexico has found far ranging impacts that may take decades to reverse. The research was published on August 7, 2013 in the journal PLoS ONE.

During the fall of 2010, scientists collected hundreds of deep-sea sediment samples from 170 sites in the Gulf of Mexico. A number of those sites (68 sites) were analyzed closely for oil contamination and the presence of bottom dwelling invertebrates.

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Scientists collecting samples from the seafloor after the 2010 Deepwater Horizon oil spill. Image Credit: Sandra Arismendez.

Reduced levels of deep sea biodiversity were found at many sites in the Gulf of Mexico where levels of oil contamination were high. The most severe impacts were detected within 3 kilometers (1.9 miles) of the wellhead where the spill originated and this area covered about 24 square kilometers (9.3 square miles) of the seafloor. Moderate impacts on benthic communities were also observed over an area of 148 square kilometers (57.1 square miles) that extended southwest and northeast of the wellhead.

Approximately 5 million barrels of oil were released during the Deepwater Horizon oil spill, and about 35–40% of that oil is thought to have remained in the deep sea.

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Estimated areas of severe (red) and moderate (orange) deep sea impacts from the 2010 oil spill in the Gulf of Mexico. Image Credit: Montagna et al. (2013) PLoS ONE, volume 8(8).

Paul Montagna, lead author of the study and Endowed Chair for Ecosystems and Modeling at Texas A&M University’s Harte Research Institute, commented on the findings in a press release. He said:

Normally, when we investigate offshore drilling sites, we find pollution within 300 to 600 yards from the site. This time it was nearly two miles from the wellhead, with identifiable impacts more than ten miles away. The effect on bottom of the vast underwater plume is something, which until now, no one was able to map. This study shows the devastating effect the spill had on the seafloor itself, and demonstrates the damage to important natural resources.

Scientists are unsure how long it may take for the benthic communities to recover. Given the cold temperatures in the deep sea, the oil could take longer to degrade than it does at the surface. It is possible that the benthic communities may take decades or longer to recover, the scientists say.

The scientists are planning to analyze additional data that were collected in 2011 to look at how conditions may be changing over time.

The research was funded by the U.S. National Oceanographic and Atmospheric Administration (NOAA), Texas A&M University, the University of Nevada, BP and the Deepwater Horizon Oil Spill National Research Damage Assessment Program.

Deepwater Horizon oil spill - May 24, 2010.  Image credit:  NASA Earth Observatory

Deepwater Horizon oil spill – May 24, 2010. Image credit: NASA Earth Observatory

Bottom line: A new study has found far ranging impacts on the biodiversity of deep sea life from the 2010 Deepwater Horizon oil spill in the Gulf of Mexico. The impacts may take decades or longer to reverse, the scientists say. The research was published on August 7, 2013 in the journal PLoS ONE.

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