This undated handout image shows microbes (C) degrading oil (upper right) in the deepwater plume from the BP oil spill in the Gulf, a study by Berkeley Lab researchers has shown. Reuters / Hoi-Ying Holman Group / Handout

By Deborah Zabarenko, Environment Correspondent
Tue Aug 24, 2010 5:25pm EDT WASHINGTON (Reuters) – A Manhattan-sized plume of oil spewed deep into the Gulf of Mexico by BP’s broken Macondo well has been consumed by a newly discovered fast-eating species of microbes, scientists reported on Tuesday.   The micro-organisms were apparently stimulated by the massive oil spill that began in April, and they degraded the hydrocarbons so efficiently that the plume is now undetectable, said Terry Hazen of Lawrence Berkeley National Laboratory. These so-called proteobacteria — Hazen calls them “bugs” — have adapted to the cold deep water where the big BP plume was observed and are able to biodegrade hydrocarbons much more quickly than expected, without significantly depleting oxygen as most known oil-depleting bacteria do. Oxygen is essential to the survival of commercially important fish and shellfish; a seasonal low-oxygen “dead zone” forms most summers in the Gulf of Mexico, caused by farm chemical run-off that flows down the Mississippi River. Hydrocarbons in the crude oil from the BP spill actually stimulated the new microbes’ ability to degrade them in cold water, Hazen and his colleagues wrote in research published on Tuesday in the journal Science. … Another factor was the consistency of the oil that came from the Macondo wellhead: light sweet Louisiana crude, an easily digestible substance for bacteria, and it was dispersed into tiny droplets, which also makes it more biodegradable. … As of Tuesday, there was no sign of the plume, Hazen said. …

Microbes ate BP oil deep-water plume: study