Cleaning up the Deepwater Horizon oil spill

On the 20th April 2010 the Deepwater Horizon oilrig exploded and sank in the Gulf of Mexico. Two days later a wellhead was found releasing thousands of barrels of oil per day, which totalled to an overall volume of 4.9 million barrels of oil released into the gulf. Response clean up crews began immediately trying to protect the coastline which included beaches, wetlands and estuaries from the incoming oil. Response crews tried to burn the oil on the surface and used skimmers and booms to stop the oil from moving. Corexit, an oil dispersant was also used to breakup the oil so it could be easily dispersed and evaporated.

The Deepwater Horizon oil spill was detrimental to the environment, however, it seems that the environment has began to fight back. Microbes have been discovered to be degrading and metabolising the oil in the gulf. Alcanivorax borkumensis is a microbe that has been linked to other oil spills such as the Exxon Valdez, the Prestige and now the Deepwater Horizon oil spill. This microbe takes over 80-90% of the microbial community when oil is present in the ocean. A.borkumensis lives in low abundance until a fuel supply such as oil becomes available and allows the microbe to rapidly multiple.

A.borkumensis degrades oil through an aerobic reaction. The microbe degrades hydrocarbons into fatty acids or carboxylic acids and then into carbon atoms. These carbon atoms are then taken into the citric acid cycle of the microbe. The carbon is then converted into energy which allows the microbe to multiply. Since this reaction is aerobic A.borkumensis requires oxygen and releases water and carbon dioxide as a by-product. This reaction successfully breaks down the oil, however, it is a long process and in the deeper ocean where oxygen is at low levels it can take months to years to degrade the oil.

Although there are some setbacks to A.borkumensis and microbes like it, scientists are trying to create a super microbe.  Thus if there is another oil spill we can use the super microbe instead of waiting for the microbes to multiply naturally. This may have detrimental effects to the environment as it will decrease the oxygen levels and increase the carbon dioxide levels at an unnatural rate. In doing this we could inflict more damage to the environment. Therefore, although we have a way to help aid our response to an oil spill we must weigh out the pros and cons before turning a natural response into a harmful response.

-Elizabeth Butcher

References

Atlas, R. M., & Hazen, T. C. (2011). Oil Biodegradation and Bioremediation: A Tale of the Two Worst Spills in U.S. History. Environmental Science Technology , 45 (16), 6709-6715.

Head, I. M., Jones, D. M., & Roling., W. F. (2006). Marine Microorganisms make a meal of oil. Nature reviews Microbiology (4), 173-182.

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