Methane lingered after Gulf blowout

by Sara E. Pratt
Tuesday, September 2, 2014

Between April 20, 2010, when BP’s Macondo oil well blew out, and July 15, when the well was finally capped, more than 4 million barrels of oil were released into the Gulf of Mexico. Along with it came up to 500,000 metric tons of natural gas, mostly methane. Previously, researchers tracking the fate of those chemicals and their impacts on the Gulf of Mexico ecosystem estimated that most of the methane had been consumed by methane-oxidizing bacteria by the end of August 2010.

New research shows that high levels of methane persisted in the water column much longer than previously thought. Melitza Crespo-Medina, a geomicrobiologist at East Carolina University (who was at the University of Georgia at the time of the study), and colleagues measured both methane concentrations in the water column and activity levels of methane-oxidizing bacteria for nine months after the blowout. The researchers found that the bacterial consumption rate soared in May and early June, but that by late June it had collapsed.

The results, reported in Nature Geoscience, show that methane lingered in the water until the end of the year, the authors wrote, and that factors other than the availability of methane were regulating its uptake by bacteria.

In an accompanying commentary, Evan Solomon, a marine geochemist at the University of Washington could lead to local hypoxia and ocean acidification."

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