Gulf-spill oil consumed by microbes far more than thought earlier

WASHINGTON - According to new research, the amount of oil consumed by microbes living at the bottom of the Gulf of Mexico may be far more than previously thought.

“Because of the ample oil and gas reserves under the Gulf of Mexico, slow seepage is a natural part of the ecosystem,” said Peter R. Girguis, associate professor of organismic and evolutionary biology at Harvard University.

“Entire communities have arisen on the seafloor that depend on these seeps. Our analysis shows that within these communities, some microbes consume methane 10 to 100 times faster than we’ve previously realized,” he said.

Girguis added that methane is just part of what spilled from the ruptured Deepwater Horizon well for three months earlier this year, and that the rate at which methane spewed from the damaged well far exceeds the flow that microbes would ordinarily encounter in the Gulf.

Using on-site mass spectrometry, Harvard research scientist Scott D. Wankel, and their colleagues were able to ascertain methane concentrations in brine pools surrounding gas seeps at the bottom of the Gulf-which were extremely high-as well as in the water column above the pools.

Combining this data with measurements of microbial activity, they were able to extrapolate just how quickly the microbes were consuming the methane.

“In fact, we observed oxidation of methane by these microbes at the highest rates ever recorded in seawater,” Girguis said.

“It appears the microbes consume much of the methane, and the rest dissipates over time into the water column.”

The study will appear in a forthcoming issue of the journal Deep-Sea Research II. (ANI)