Microbes on sea floor feasting merrily on oil

October 1st, 2008 - 1:45 pm ICT by IANS  

Washington, Oct 1 (IANS) Thousands of feet below the surface of the sea, off the shores of Santa Barbara, single-celled organisms are busy feasting on oil, seeping from the ocean floor.New research led by David Valentine of the University of California Santa Barbara (UCSB) and Chris Reddy of Woods Hole Oceanographic Institution in Massachusetts has shed new light on just how extensive their diet can be.

Valentine, Reddy, George Wardlaw of UCSB and three other co-authors detailed how the microbes are dining on thousands of compounds that make up the oil seeping from the sea floor, said a release of UCSB and Woods Hole Institution.

Their report was published in the Wednesday edition of Environmental Science & Technology.

“It takes a special organism to live half a mile deep in the earth and eat oil for a living,” said Valentine, an associate professor at UCSB. “There’s this incredibly complex diet for organisms down there eating the oil. It’s like a buffet.”

And, the researchers found, there may be one other byproduct being produced by all of this munching on oil - natural gas. “They’re eating the oil, and probably making natural gas out of it,” Valentine said.

“It’s actually a whole consortium of organisms - some that are eating the oil and producing intermediate products, and then those intermediate products are converted by another group to natural gas,” he said.

Reddy, a marine chemist, said the research provides important new clues in the study of petroleum. “The biggest surprise was that microbes living without oxygen could eat so many compounds that compose crude oil,” he said.

“Prior to this study, only a handful of compounds were shown, mostly in laboratory studies, to be degraded anaerobically. This is a major leap forward in understanding petroleum geochemistry and microbiology.”

The diet of the single-cell microbes is far more diverse than previously thought, Valentine said. “They ate around 1,000 of the 1,500 compounds we could trace, and presumably are eating many more.”

Research for this project began seven years ago and much of the testing was done at one of the planet’s best natural labs. “We have the world’s most prolific hydrocarbon seep field sitting right offshore of Santa Barbara, about two miles out,” Valentine said. “We have something on the order of 100 barrels of oil a day coming up from the sea floor.”

By studying samples from the subsurface, the ocean floor, the mid-water, and then from the surface, the researchers could determine how much of the oil was being degraded and digested by the microbes.

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