Bacteria help to clean up Deepwater Horizon spill

Debora MacKenzie in New Scientist: Zoom in on the Deepwater Horizon oil slick and you will find a motley community of critters hard at work breaking down the oil: bacteria. At the annual meeting of the American Society for Microbiology in San Diego, California, this week, Jay Grimes of the University of Southern Mississippi in Hattiesburg reported that over the past few years, researchers have found that dozens of different kinds of marine bacteria have a healthy appetite for oil.

He said that water samples from the Gulf of Mexico are showing signs that marine bacteria are already pitching in to help with clean-up efforts, and that populations of these bacteria in this area are likely to boom as they feast on the oil from the Deepwater Horizon disaster.

Among these are members of the Vibrio family, which includes the species that causes cholera. Grimes cautions that there is no evidence that this species is one of those that breaks down oil, although other Vibrios that cause human infections do. "The Vibrios use breakdown products of oil," says Rita Colwell of the University of Maryland in College Park. "When [the oil from Deepwater Horizon] reaches the estuary, Vibrios very likely will increase."

…"Now we plan to see how the microbial community evolves when you give it oil," says Grimes. He hopes to screen bacteria from oil-affected water for the DNA of oil-eating enzymes, and use this to determine their species.

"This blowout could permanently reshuffle the microbial community in the Gulf," Grimes says. In previous research he found that Vibrio became the dominant type of marine bacteria off the south-eastern US as oil tanker traffic increased after the 1970s.
Long-term threat

For now the oil mainly threatens larval fish clinging to the underside of mats of seaweed. "I hope most of the oil will stay out to sea," says Grimes. "It may kill a year's production of fish, but if it hits the coastal marshes, it could be there for a decade." At particular risk are coastal salt marshes….

Clouds of smoke billow up from controlled burns taking place in the Gulf of Mexico May 19, 2010. The controlled burns were set to reduce the amount of oil in the water following the Deepwater Horizon oil spill. Image from the US Coast Guard