Have you seen those BP commercials that talk about how the Gulf Coast is “open for business”? These ads are little more than BP-sponsored propaganda to assuage people’s fears about swimming in water contaminated by the 2010 Deepwater Horizon spill. (Spoiler: there’s still plenty of oil washing up on Gulf Coast beaches). BP seems to think that their controversial dispersants did the trick, breaking down the oil until it was no longer visible on the ocean’s surface. But a recent study of the Gulf Coast shows that naturally occurring bacteria – not the Corexit BP dumped by the airplane full – are responsible for cleaning up the majority of the spill.
Researchers from the University of Rochester and Texas A&M University recently published the results of a study that analyzed an extensive set of data taken from the Gulf. In it they demonstrate how over a period of five months following the disastrous 2010 Deepwater Horizon explosion and oil spill, naturally-occurring bacteria that exist in the Gulf of Mexico consumed and removed at least 200,000 tons of oil and natural gas that spewed into the deep Gulf from the ruptured Macondo well head.
The study proves what environmentalists have been saying from the beginning: dispersants don’t “clean up” the oil, they just make it smaller. However, the scientists say that this may have made it easier for the bacteria to do their job. “Interestingly, the oil and gas consumption rate was correlated with the addition of dispersants at the wellhead,” said co-author John Kessler of the University of Rochester. “While there is still much to learn about the appropriateness of using dispersants in a natural ecosystem, our results suggest it made the released hydrocarbons more available to the native Gulf of Mexico microorganisms. ”
However, it seems that while the bacterial feast may have helped clean up the oil, it didn’t necessarily make the Gulf of Mexico a healthier stretch of ocean. “When bacteria consume oil and gas, they use up oxygen and release carbon dioxide, just as humans do when we breathe,” explained graduate research assistant Mengran Du from Texas A&M University. “When bacteria die and decompose, that uses up still more oxygen. Both these processes remove oxygen from the water.”
Coupled with the already acidic nature of the Gulf of Mexico thanks to warming temperatures brought on by climate change, this type of mass oxygen depletion could spell disaster for the marine species that were able to survive.