The vital role of bacteria during oil spills

An international team of scientists, led by Dr. Tony Gutierrez of Heriot-Watt University, has revealed the first evidence that certain species of bacteria thrived on the oil that was released into the Gulf of Mexico during the Deepwater Horizon spill.

The Deepwater Horizon Spill  

The blow-out of the Deepwater Horizon oil rig off the Louisiana coast on April 20 of 2010 is marked as the worst environmental disaster in US history and one of the most devastating maritime accidental spills worldwide.

Around 700,000 tonnes of crude oil leaked into the Gulf of Mexico over a period of nearly three months, impacting vast stretches of coastline and open waters in the Gulf. Microbes, in particular bacteria, are known to perform a fundamental role in the degradation and ultimate removal of oil after it enters the marine environment, and this was certainly the case at Deepwater Horizon.

How the microbial community responded

Several scientific publications have described how the microbial community in the Gulf responded to the massive influx of oil released from the Deepwater Horizon blowout, however, little evidence was presented to confirm that any of the identified bacteria were capable of degrading the oil.

Using sophisticated molecular techniques and a collection of hydrocarbon molecules containing specially-labelled carbon atoms, the international team of scientists identified various species of bacteria in surface oil slicks and deeper waters in the Gulf and confirmed their ability to degrade the oil.

This work presented unequivocal evidence on the capacity for some of the most dominant bacteria found in the Gulf during the spill to have contributed a significant role in the removal of the oil. The team is also the first to report on the isolation of the most dominant oil-degrading bacteria from the surface oil slicks.

Oil-degrading bacteria isolated from oil slicks that formed on the sea surface in the Gulf of Mexicoduring the Deepwater Horizon oil spill. The green dots are the bacteria, called Alteromonas species, shown here amongst droplets of crude oil (large green blobs).

The important role of micro-organisms

Dr Gutierrez's team's findings further increase our understanding on the fate of the oil that spilled into the Gulf of Mexico, and reinforces the important roles that micro-organisms play in our environment, such as in cleaning up oil spills. Without oil-degrading bacteria, the Gulf of Mexico, and the world's oceans and seas for that matter, would be continuously covered in a slick of oil.