Bacteria's Nitrogen-Rich Diet Helped Clean Up Gulf Of Mexico Oil Spill
August 30, 2013

Bacteria’s Nitrogen-Rich Diet Helped Clean Up Gulf Of Mexico Oil Spill

Brett Smith for - Your Universe Online

Releasing 210 million gallons of crude into the Gulf of Mexico, the 2010 Deepwater Horizon oil spill has been described as one of the greatest man-made ecological disasters to ever impact the region.

However, the native bacteria on gulf beaches were able to metabolize the contamination from the spill by supplementing their diet with nitrogen, according to research being presented today at the European Association of Geochemistry’s Goldschmidt 2013 conference in Florence, Italy.

According to a genetic analysis performed by Georgia Institute of Technology in Atlanta microbiologist Joel Kostka and a team of researchers, by fixing nitrogen from the air, gulf bacteria were able to thrive on a diet of oil. The research could pave the way for more advanced oil spill cleanup techniques, researchers said.

"Oil is a natural product, made of decayed plants and animals, and so is similar to the normal food sources for these bacteria,” Kostka explained. "But because oil is low in nutrients such as nitrogen, this can limit how fast the bacteria grow and how quickly they are able to break down the oil. Our analysis showed that some bacteria are able to solve this problem themselves -- by getting their own nitrogen from the air."

The study included more than 500 samples taken over two years from Pensacola Beach in the Gulf of Mexico starting in June 2010, when oil first came ashore. The genetic analysis showed which bacteria were present and how they responded to the changing conditions. The researchers look at certain genes as markers of different types of activity, from nitrogen fixing to phosphorus uptake.

"By understanding how the oil is degraded by microbes, which microbes do the work, and the impact of the surrounding environmental conditions, we can develop ways to intervene to support the natural clean-up process," Kostka said. "However, we need to do this in a very measured and targeted way, to avoid long-term, unintended damage to the ecosystem.”

“For example, in the past, nitrogen fertilizer has been sprayed onto contaminated beaches to speed up the work of the bacteria,” he added. “Our analysis shows that, where bacteria can get this nitrogen naturally, such drastic intervention may not be necessary."

The research team said their work could make it possible to determine which beaches are most effective at self-cleaning and target cleanup toward the most vulnerable areas.

The research also showed that some bacteria that are very important to the ecosystem were hit hard by the contamination starting in June 2010.

"There's a tendency to focus on the short-term, visible effects of an oil spill on the beach and assume that once the beach looks 'clean' then all is back to normal," Kostka said. "Our analysis shows some of the invisible impact in the loss of these important microbes. We need to be aware of the long-term chronic damage both a spill -- and in some cases our attempts to deal with it -- can cause."

Research presented earlier this year at the American Chemical Society conference in New Orleans suggested that the Gulf has a natural mechanism capable of breaking down spilled oil at a significant rate.