Surprisingly, practically all of the methane that accompanied nearly five million barrels of oil leaked into the northern Gulf of Mexico (map) has been devoured by giant bacterial blooms, a new study says. Methane, the main component of natural gas, is typically found with oil.
(Read more about how nature is fighting back against the oil spill.)
The Deepwater Horizon oil rig burned and sank last April, and the damaged wellhead on the seafloor below was permanently capped in July.
"We thought it would probably be something on the order of a year or so until the methane disappeared," said study leader David Valentine, a microbial geochemist at the University of California, Santa Barbara. "Instead we found that by mid-September it was completely gone."
Deep, water-dissolved methane was the single most abundant hydrocarbon released during the spill, making up about 20 percent of the flow from the wellhead, Valentine and his team estimated.
However, the discovery doesn't mean that the oil itself is gone. The team found oil nearly everywhere in the deep water—suggesting that oil-water mixing was widespread, and that some ingredients of the oil haven't completely degraded.
