Bacteria gobbled methane from BP spill: scientists

By Deborah Zabarenko, Environment Correspondent; Editing by Peter Cooney
Thu Jan 6, 2011 4:17pm EST WASHINGTON (Reuters) – Bacteria ate nearly all the potentially climate-warming methane that spewed from BP’s broken wellhead in the Gulf of Mexico last year, scientists reported on Thursday. Nearly 200,000 tons of methane — more than any other single hydrocarbon emitted in the accident — were released from the wellhead, and nearly all of it went into the deep water of the Gulf, researcher David Valentine of the University of California-Santa Barbara said in a telephone interview. Bacteria managed to take in the methane before it could rise from the sea bottom and be released into the atmosphere, but the process contributed to a loss of about 1 million tons of dissolved oxygen in areas southwest of the well. That sounds like a lot of oxygen loss, but it was widely spread out, so that the bacterial munching did not contribute to a life-sapping low-oxygen condition known as hypoxia, said Valentine, whose study was published in the journal Science. … The BP spill offered an “accidental experiment” that showed particular bacteria with an all-methane diet multiplied quickly as the methane spread with the underwater plume from the broken well. Peak consumption of methane probably came in late July and early August, Valentine said. Other organisms dealt with other hydrocarbons, including ethane and propane emitted in the worst offshore oil spill in U.S. history. The methane-eating bacteria were the last to the hydrocarbon banquet, and based on past observation, the scientists questioned whether they could do the job. “Given observations about how slowly methane is normally consumed, we didn’t think the (bacteria) population was up to the challenge at all … we thought it would be a lot slower,” Valentine said. …