Oil-eating bacteria came to the rescue

Microscopic bacteria played a crucial role in the cleanup of the devastating 2010 BP Gulf of Mexico oil spill, scientists who decoded the genomes of the oil-eating organisms reported Monday.

The findings published in the Nature Microbiology journal suggest that certain bacteria have far greater potential for containing chemical pollution in the ocean than previously thought.

An explosion on the Deepwater Horizon oil rig in 2010 killed 11 men off the coast of Louisiana and caused 134 million gallons (507 million litres) of oil to spew into Gulf waters.

It took 87 days to cap the out of control well some 1,500 metres (5,000 feet) below sea level, and the oil slick stretched across an area the size of Virgina. 

Beaches were blackened in five US states, and the region's tourism and fishing industries were devastated.

Massive resources were mobilised to clean up the mess, and BP paid out a record $20.8 billion (18.2 billion euros) to settle claims for damages.

As the disaster unfolded, communities of bacteria grew unusually fast, and helped to eat away at the chemicals that had contaminated the sea water.

- 'Surprisingly capable' -

There were as many as 1,000 different types of chemical compounds to be dispersed.

While it was clear that bacteria assisted in the clean up, scientists did not know much about the genetic traits that caused the process, or the full range of the single-cell organisms involved.

Assistant professor Brett Baker and post-doctoral researcher Nina Dombrowski, both from the University of Texas at Austin, sequenced the DNA of the oil-eating microbes to find out more.
"We found a number of bacteria surprisingly capable of dealing with the more dangerous compounds," Dombrowski said in a statement.

"This has implications for future oil spills and how we take advantage of the natural environmental response."

Oil has a complicated chemical makeup, but consists broadly of two main compounds. 

Alkanes are relatively easy for bacteria to break down. Aromatic hydrocarbons are not.

But not only did the gene sequencing reveal that several bacteria -- including one called Alcanivorax, and another named Neptuniibacter -- could handle the hydrocarbons.

But it also showed how various species worked together to maximise the viability of the whole microbial community.

"We used new methods to obtain genomes of bacteria that haven't been grown in the lab to enhance our understanding of how they consume oil in nature," Baker said.

The scientists even found some species that assisted with the post-cleanup, eating the chemicals that had been added to the water to absorb or dissolve the oil.

While not as harmful as the oil itself, these dispersants can damage the environment too.

Dombrowski said that humans had a responsibility to help maintain "a healthy and diverse bacterial community". 

Source: AFP