The Gulf of Mexico oil spill has revealed a previously unknown type of oil-eating microbe, which is suddenly flourishing, according to scientists who took the first direct measurements of undersea bacteria feeding on the oil spill.
Results announced Tuesday by researchers from California’s Lawrence Berkeley National Laboratory indicate the Gulf of Mexico may be rebounding faster than many had expected from the largest accidental offshore oil spill in history.
Scientists discovered the new microbe while studying the underwater dispersion of millions of gallons of oil spilled into the Gulf following the explosion of BP’s Deepwater Horizon drilling rig.
And the microbe works without significantly depleting oxygen in the water, researchers led by Terry Hazen at Lawrence Berkeley National Laboratory in the online journal Science Express.
“Our findings, which provide the first data ever on microbial activity from a deepwater dispersed oil plume, suggest” a great potential for bacteria to help dispose of oil plumes in the deep-sea, Hazen said in a statement.
Environmentalists have raised concerns about the giant oil spill and the underwater plume of dispersed oil, particularly its potential effects on sea life. A report just last week described a 22-mile long underwater mist of tiny oil droplets.
“Our findings show that the influx of oil profoundly altered the microbial community by significantly stimulating deep-sea” cold temperature bacteria that are closely related to known petroleum-degrading microbes, Hazen reported.
Before the spill the microbes in the deepest parts of the Gulf were not well known and there was little carbon present in the area of cool temperatures and high pressure.
“We deployed on two ships to determine the physical, chemical and microbiological properties of the deepwater oil plume,” Hazen said. “The oil escaping from the damaged wellhead represented an enormous carbon input to the water column.”
Their findings are based on more than 200 samples collected from 17 deepwater sites between May 25 and June 2. They found that the dominant microbe in the oil plume is a new species, closely related to members of Oceanospirillales.
Scientists had been concerned that oil-eating activity by microbes would consume large amounts of oxygen in the water, creating a “dead zone” dangerous to other life. But the new study found that oxygen saturation outside the oil plume was 67 percent, while within the plume it was 59 percent.
Also last week, scientists from the Woods Hole Oceanographic Institution argued that, based on their analysis, the 22-mile-long sub-surface oil plume may linger underwater for months.
But the Lawrence Berkeley researchers said their work on microbes shows it may already be gone. “There is real disagreement here,” said microbiologist Jim Spain at the Georgia Institute of Technology.
At the meeting, Dr. Hazen reported that water samples he and his colleagues have collected since the damaged well was capped last month suggest the plume of petroleum hydrocarbons is now undetectable.
It’s consumed by oil-eating bacteria or carried away from the immediate vicinity of the damaged well by currents. That observation isn’t included in the Science article.
Dr. Hazen and other microbiologists are convinced that bacteria have already eliminated the hazard posed by the plume. “We no longer see any deep plumes that can be attributed to the leak,” Dr. Hazen said.
However, some marine chemists and oceanographers suspect that the current carried the plume out of the immediate spill zone—and, for the time being, out of the range of scientific sensors.
“The plume is not a stationary object,” said Richard Camilli at the Woods Hole Oceanographic Institution, chief scientist for a research team that first mapped the underwater plume. By his calculation, the diluted plume could be hundreds of miles from the damaged well by now. [via Wall Street Journal, San Francisco Chronicle and Washington Post]