From NY Times news website story on this topic:
Oil Spill Cleanup Workers Include Many Very, Very Small Ones
By WILLIAM J. BROAD
Published: August 4, 2010
Among the hidden stars of the gulf cleanup is an oil-hungry bacterium that Dr. Seuss could have named — Alcanivorax. It and fellow microbes are breaking down a significant amount of the oil that gushed into the environment from BP’s runaway well, scientists say. The microbial feasting is known as biodegradation.
On Wednesday, a report released by the National Oceanic and Atmospheric Administration said early observations showed that the oil from the Deepwater Horizon spill “is biodegrading quickly,” adding that scientists were working to measure how quickly and how much of the escaped oil the microbial hordes could consume.
“Until it is biodegraded, naturally or chemically dispersed oil, even in small amounts, can be toxic to vulnerable species,” the report says in pointing to the importance of the microbes.
The report said the swarms were dining on most remaining aspects of the spill — dispersed oil as well as oil forming a sheen on or just below the surface.
“Colleagues who have been sampling tell me that the intrinsic biodegration rates are high,” said Ronald M. Atlas, a microbiologist at the University of Louisville and past president of the American Society for Microbiology. “I believe that most of the oil will not have a significant impact. That’s been the story with spills that stay offshore.”
Dr. Atlas cautioned, however, that microbe degradation in polluted marshes “should be considerably slower.”
And other scientists warn that the sudden appearance of swarms of oil-hungry microbes in the Gulf of Mexico could have drawbacks, saying they might consume so much oxygen that oxygen levels drop precipitously, threatening other sea life.
Samantha B. Joye, a marine scientist at the University of Georgia, told a House science subcommittee this year that drops in oxygen could especially threaten an unusual class of creatures that also live on oil: communities of clams, mussels and tube worms that flourish in the sunless depths of the gulf.
The gulf proper has an enormous ability to break down oil because thousands of natural seeps in the seabed leak oil and gas at a fairly steady rate, and have for millions of years. None are close in size to the Deepwater Horizon leak. But over the ages, swarms of microbes and other creatures have learned how to live on petrochemicals flowing from the fissures, giving the gulf some powers of natural recuperation.
Scientists say a star of the feasting is Alcanivorax — its name alluding to its voracious appetite for alkanes, some of the main chemicals of natural gas and petroleum. In unspoiled environments around the world, the marine bacterium exists in limited numbers. But it rapidly multiplies in oil-contaminated waters, as scientists portray the usual state of the gulf.
“It’s preadapted to crude oil,” said Roger Sassen, a gulf specialist recently retired from Texas A&M University who has long argued that natural remediation would cleanse its waters. “The image of this spill being a complete disaster is not true.”
In the report on Wednesday, the federal panel echoed that optimism in diplomatic language.
“It is well known,” the report said, “that bacteria that break down the dispersed and weathered surface oil are abundant in the Gulf of Mexico in large part because of the warm water, the favorable nutrient and oxygen levels, and the fact that oil regularly enters the Gulf of Mexico through natural seeps.”
Wednesday’s report also highlighted the effects of oil dispersion — a strategy that some critics of BP had faulted, especially as the company pumped chemicals into the depths that were meant to scatter the gushing oil. The report said dispersion at the surface and in the deep “increases the likelihood that the oil will be biodegraded” by billions of oil-eating microbes.
Dr. Atlas of the University of Louisville agreed. But he noted that “the extensive use of dispersants has been of toxicological concern.”
Hopes for the natural remediation of oil spills at sea have grown in recent years as scientists have discovered a new class of microbes known as hydrocarbonoclastic, a group that includes Alcanivorax. The name hydrocarbonoclastic denotes the disassembly of hydrocarbons, the building blocks of oil.
A 2003 report by the National Research Council, “Oil in the Sea,” called the biodegradation of hydrocarbons “one of the principal removal mechanisms in the aquatic environment,” as well as “a premiere research area.”
That same year, a team of German scientists reported that it had deciphered the genome of Alcanivorax, shedding light on the microbe’s genetic structure and raising the possibility of enhancing its oil-eating abilities.
Jay Lennon, a microbial ecologist at Michigan State University, said the gene sequencing helped show how Alcanivorax could break down the surface tension in fluids and attack oil.
“Micro-organisms are pretty amazing,” he said. “If there’s a way for them to make a living, they’ll do it.”
