Washington: Bacteria consumed the methane released from the Deepwater Horizon oil spill in the Gulf of Mexico within about four months, say scientists.
"It was remarkable. We had gone out there assuming that there would be plenty of methane still there and the fact was that it was all gone," Discovery News quoted John Kessler of Texas A n M University in College Station, as saying.
The team had seen a different picture when they sampled the area in June 2010, before the July 15 sealing of the well. Methane levels were high, dissolved in plumes about two-thirds of the way to the sea floor, and decomposition rates were low.
"It seemed that methane would be there for a much longer time period, possibly several years," said Kessler.
But when the team returned in three cruises between Aug. 18 and Oct. 4, expecting to track the slow degradation of methane, they found that it all was gone. Concentrations had returned to background levels.
Methane-consuming microbes comprised the highest proportion researchers had ever seen in the overall microbial community, and the oxygen levels the team measured could only be explained by complete consumption of the methane. This evidence supported the idea that it was microbes that made the methane disappear, said Kessler.
The findings have also provided insight into what might happens in a future natural methane release from the sea floor.
While the team’s findings suggest that methane-chomping microorganisms have the potential to consume large quantities of released methane, "We can’t generalize these findings to the greater planet," he said.
The findings were published in the journal Science.
First Published: Friday, January 07, 2011, 18:14