The damage caused by the 2010 Deepwater Horizon blowout in the Gulf of Mexico may have been partially remedied by the Gulf itself.
According to research presented at the American Chemical Society conference this week, micro-organisms in the ocean feed on the oil when they detect methane in the water. Oil dispersant chemicals, by contrast, were found not to do any long-term good to the Gulf, and even hindered the Gulf's self-cleaning efforts.
These oil-degrading microbes—"oil-seeking missiles" as scientist Terry Hazen of the University of Tennessee, Knoxville, calls them—are familiar with oil spills, as there has been natural seepage of oil from the ocean bed for millions of years. A 2003 report from the U.S. National Academy of Sciences puts the amount of seep in the Gulf of Mexico at around 154,000 U.S. tons per year.
The Deepwater spill created a sudden influx of methane in the water, which meant the methanotrophs—the microbes that feed on the gas—increase in population. They gobble up the methane, and when that is gone, they go for anything else they can chew on. "At that point, they degrade anything else that's there fortuitously," said Hazen. "And they'll degrade it down below what would be usable as a carbon and energy source—so it's really sort of a "deep-cleaning" effect.
Hazen believes that the Gulf may have become cleaner more quickly than was expected, but he remains unsure of the state of its ecosystem. "Fish and bacteria and plankton and everything else were swimming through that oil, and we don't know what long-term effects that'll have."
The oil spill was one of the most disastrous in recent history, and led to the ousting of BP's chief executive, Tony Hayward. Last year, the energy firm paid a record $4.5 billion fine handed down by the U.S. Department of Justice.
[Image by Flickr user ideum]