New bacteria degrades oil faster, in deep, cold water: study
Washington (AFP) Aug 24, 2010
A new species of bacteria found in the Gulf of Mexico degrades oil faster at deeper and colder depths than expected, scientists said Tuesday in a study that could explain how the BP oil spill has mostly disappeared.
The bacteria not only speeds up the bio-degradation of crude oil, but does it without depleting vital oxygen levels in the water, said the scientists who analyzed in May a plume of oil at a depth of 1,000-1,200 meters (3,600-4,000 feet), extending 16 kilometers (10 miles) out from the broken BP wellhead.
"Our findings, which provide the first data ever on microbial activity from a deepwater dispersed oil plume, suggest that a great potential for intrinsic bioremediation of oil plumes exists in the deep-sea," said Terry Hazen, a microbial ecologist with Berkeley Lab's Earth Sciences Division and lead author of the study.
"These findings also show that psychrophilic (cold temperature) oil-degrading microbial populations and their associated microbial communities play a significant role in controlling the ultimate fates and consequences of deep-sea oil plumes in the Gulf of Mexico," he added.
The bacteria live in waters as cold as five degrees Celsius (41 Fahrenheit) in a relatively unexplored microbial habitat in the Gulf of Mexico, where the pressure is enormous and there is normally little carbon present.
Once the BP wellhead was plugged on July 15, nearly three months after an explosion unleashed the worst oil spill in US history, US government investigators said 74 percent of the more than four million barrels of oil that leaked had evaporated, biodegraded or was recovered by mechanical means.
The Berkeley study attributed the faster than expected oil degradation in such cold water, in part, to "the nature of Gulf light crude, which contains a large volatile component that is more biodegradable."
Other accelerating factors, the scientists added, may have been the chemical dispersant Corexit used by BP at the source of the leak -- at 1,500 meters (nearly 5,000 feet) -- which broke up the oil into smaller particles, as well as the low overall concentrations of oil in the plume studied.
"In addition, frequent episodic oil leaks from natural seeps in the Gulf seabed may have led to adaptations over long periods of time by the deep-sea microbial community that speed up hydrocarbon degradation rates," they said.
The study also dispelled some oceanographers' fear that the oil bio-degradation would deplete oxygen levels in the water, creating so-called "dead-zones" where life cannot be sustained.
The Berkeley study found that oxygen saturation outside the plume was 67-percent while within the plume it was 59-percent.
The study published in the online edition of Science magazine contradicts the results of a Woods Hole Oceanographic Institution research published Friday by the same magazine that said oil degradation would be slower in the cold depths of the Gulf.
It also appears to refute a University of Georgia study from a week ago that said 80 percent the oil leaked into the Gulf was still drifting beneath the surface of the Gulf posing and slowly decomposing, posing a significant threat to ecosystems in the area.
earlier related report
Twenty nations held two days of talks in Washington in first-of-a-kind shale gas talks initiated by the United States, where some forecast that shale -- a miniscule presence a decade ago -- could dominate the gas market by 2030.
Shale gas comes from deep reserves that were thought inaccessible until the advent of new drilling methods. But costs still are usually above conventional gas, and some environmentalists worry about pollution in drinking water.
US officials believe that developing shale gas would provide fast-growing China and India with a cleaner alternative to coal, a key culprit in carbon emissions blamed by scientists for a dangerous warming of the planet.
In Europe, shale gas could also reduce reliance on energy heavyweight Russia. Last year, a dispute between Russia and Ukraine cut off Russian gas to several members of the European Union.
"The main reasons for doing it are national security and climate security," David Goldwyn, the State Department's coordinator on international energy affairs, said of the conference.
"In Eastern Europe in particular, it's really diversity of supply. It's a national security issue," Goldwyn told reporters.
"For China and India, it's both climate security and economic security, because they have large demand for resources and the market is volatile," he said.
Another potential reason -- the United States, and to an extent Canada, have an edge in shale gas. Last year, the United States overtook Russia for the first time in decades as the world's top gas producer.
"In this country it's entirely possible, if things continue on trend, that we would have the ability to export gas extracted from shale, liquefy it and export it overseas," Goldwyn said.
He said US energy companies made presentations during the talks, but that the main focus was on explaining to other countries how to put in place a regulatory framework to develop shale gas.
"Our goal in this conference was really to be a regulatory conference, rather than trade promotion," he said, describing other delegates as "enthusiastic, but careful" on shale gas.
India's biggest private firm, Reliance Industries, has been eager to pursue shale gas, investing nearly 3.5 billion dollars since April in joint ventures for fields in the United States.
China has been trying to catch up, with the state-owned China National Petroleum Corp reportedly recently setting up a research center for shale gas.
But some environmentalists are not convinced that shale gas is the way to go.
Bentley Johnson, legislative representative at the Washington-based National Wildlife Federation's Public Lands Campaign, said that while gas burned cleaner than other fossil fuels, the effect was less when factoring in the energy expended to extract and transport it.
Even more worrisome, he said, are dangers to drinking water from hydraulic fracturing -- injecting water and chemicals deep underground to bring out gas.
"It makes more sense to invest in truly clean renewable energies such as wind and solar rather than staying on a traditional fossil fuel way of getting our energy," Johnson said.
"As far as the solution to worldwide energy demands in growing economies like China, I don't think it's the answer," he said of shale gas.
In the documentary "Gasland," which won the Special Jury Prize at this year's Sundance Film Festival, filmmaker Josh Fox showed families in a drilling area whose tap water was even flammable.
Asked about environmentalists' concerns, Goldwyn said they showed the need for regulations -- a "huge part" of the 20-nation discussions.
"If done responsibly, it can be done safely," he said.
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