 feast on specific hydrocarbons in the Gulf of Mexico oil spill.)
OIL EATERS: Newly discovered microbes (circled here in red) feast on specific hydrocarbons in the Gulf of Mexico oil spill.
Image: © Science / AAAS
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These are boom times for oil-eating microbes in the deep waters of the Gulf of Mexico, thanks to BP's Deepwater Horizon accident that has added some 600 million liters of hydrocarbons to those waters. And now research published online in Science on August 24 shows that an array of new and unclassified oil-eating bacteria are feasting on the newly rich resource of hydrocarbons.
Microbial ecologist Terry Hazen of Lawrence Berkeley National Laboratory (LBNL) and his colleagues used two ships to collect 200 samples from 17 deep water locations between May 25 and June 2. The samples revealed a broad array of microbes, closely related to those of the Oceanospirillales family that includes such oil eaters as Oleispirea antarctica, Oceaniserpentilla haliotis and Thalassolituus oleivorans. These new microbes—led by one particular unusually long (20 microns), yet to be named species that made up more roughly 95 percent of the community responding to the spill—had consumed roughly 8 percent of the available oxygen in these cold, deep waters as they busily converted hydrocarbons into more microbial cells, limited only by a lack of iron. As a result, oxygen saturation at depth dropped from an average of 67 percent to 59 percent while microbial cell concentrations doubled to 5,510 cells per milliliter compared with just 2,730 cells per milliliter outside the plume. So far, no one has measured an impact on other ocean life from the drop in oxygen, which is unexpectedly small, a fact that Hazen ascribes to the dispersed nature of the oil plume. "Concentrations of oil in this deep plume are so low that we don't see oxygen depletion," he explains.
The microbes did this at extremely low temperatures—4.7 degrees Celsius—that slow ordinary bacterium's metabolism as well as under high pressures. And it was a group of roughly 16 gamma-Proteobacteria species doing the bulk of the work. Genetic testing revealed these microbes engaged the same cellular equipment as known oil-eaters, such as Alcanivorax borkumensis from the Oceanospirillales order, to break down the hydrocarbons. Large quantities of the various genes necessary to such oil-eating work were found in hydrocarbon-contaminated waters compared to untainted waters.
The scientists also found that the microbes were making quick work of many of the hydrocarbons in the deep sea plumes. Alkanes, for instance—a hydrocarbon easily digested by such bacteria—could be consumed in as little as a day. In fact, the alkanes in these samples lasted, at best, roughly six days in the presence of microbes. Hazen and his colleagues attribute that quick work to the large contingent of such volatile hydrocarbons that are readily biodegradeable in the Louisiana light sweet crude spilled as well as the breaking up of the oil into small particles by chemical dispersants.
"Microbes eat [hydrocarbons] like we eat at a buffet: they like some compounds better than others," explained marine chemist Chris Reddy of the Woods Hole Oceanographic Institution during an August 19 press conference announcing the existence of such oil plumes—though their findings also published in Science suggested microbes were consuming the plume slowly in late June due to low levels of oxygen depletion. "They leave behind a fingerprint of what they chose to eat," Reddy explained.
In fact, some scientists disagree with the analysis of the biodegradation rates by Hazen and his colleagues. "The microbiology is very convincing," but the extrapolation to the rate of hydrocarbon consumption "is potentially flawed and gives the wrong impression," says biogeochemist David Valentine of the University of California, Santa Barbara, who is also attempting to characterize the microbial response to the oil spewing from BP's Macondo 252 well in the Gulf of Mexico. "They are probably measuring the dilution time for the early plume, more so than the biodegradation rate." In other words, the microbes don't eat the alkanes in the hydrocarbon plume in less than a week; rather these compounds get diluted among all the trillions of gallons of seawater in the Gulf.
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12 Comments
Add CommentIt sure seems like there are a lot of environmentalists that are sad that more damage wasn't done and the impact of this is nothing near what was predicted.
Reply | Report Abuse | Link to thisThis appears to be very good news. At least this is one industry funded study that is not likely biased by their funding source's interests.
Reply | Report Abuse | Link to thisIn hindsight, this isn't too surprising. Some oil seeps are naturally present, so oil-eating microbes have had a long time to evolve. The sudden presence of abundant food should cause a population explosion, and it has. As the article suggests, the concern is not that the contamination will persist, but rather that it will be consumed too fast, both because of the potential for oxygen depletion and because, when the food is gone, there will be a lot of dead microbes that will have to be consumed as the next step in the process.
Reply | Report Abuse | Link to thisSome question that came to mind...
Reply | Report Abuse | Link to thisI'm wondering how the bacterias' CO2 output compares to a combustion engine's on a per liter consumed basis?
And how fast does one liter of oil get consumed depending on its dilution?
And how is the oil consumption rate affected by dispersant driven dilution in comparison to "natural" dilution?
SciAm - Why do you continue to let this SPAMMER "zhenyaya" post?
Reply | Report Abuse | Link to thisIt seems like sinking some old supertankers filled with liquid oxygen in the gulf could help with the oil and the dead zone.
Reply | Report Abuse | Link to thisThere are still many questions and misleading statement from this researcher. Such as: "We can't detect anything. It's mostly biodegradation probably.". lol, nice little probably added in there, allows for a great degree of plausible deniability. Realistically though, most of the oil is dispersed. toxins will quickly get absorbed by all the organisms and will compund up the food chain. Oil eating organisms are great, but the article also states that they do not eat everything in the oil, they are picky creatures. Heavy metals are probably not consumed.
Reply | Report Abuse | Link to thisThis is the worse environmental disaster in US history. Anyone who thinks this is perfectly acceptable or that this is just the cost of doing business is concerned only with maintaining the status quo, and not progressive technology. We don't need million year old dead fermenting dinasours for burning anymore, it's barberic; we've harnessed the power of the atom which is far greater than any chemical process (such as burning). If you don't beleive or care about global warming fine, ignore it, focus on the health effects of fossil fuels... traditionally, 25% of the population would get cancer within their life, before the industrial revolution... Now, 38% of the population will get cancer... Smoking rates are down dramatically from around 60% to 20%. We have a definite cure for 1/3 of all cancer, simply stop burning and putting carcinogens in the air.
I agree, there has been significant overinflation by environmentalist AND there has been significant UNDERDEFLATION by skeptics. Fact of the matter, this is a terrible disaster that will have only negative ripples in the food chain for decades, nothing positive will come from this.
“A third of the living creatures in the sea died, and a third of the ships were destroyed.” (Revelation 8:9). While the Gulf oil spill may not be the fulfillment of that prophecy, the Gulf oil spill does show that something like that could happen. The idea isn’t so farfetched. “He who testifies to these things says, ‘Yes, I am coming soon.’ Amen. Come, Lord Jesus.” (Revelation 22:20).
Reply | Report Abuse | Link to thisSo, scientists funded with $500 million of BP's money are giving us positive news!
Reply | Report Abuse | Link to thisI am not discounting the fact that there are an abundance of oil eating microbes now, but the overall positive spin of the scientists involved seems unwarranted.
Big Suprise! BP Oil buying research that results in supporting the disappearance of the oil plume and miraculous new microbes that eat oil. I have a bridge in Brooklyn and a swamp in Florida. Anyone buying?
Reply | Report Abuse | Link to thisBig suprise! Scientific research being supported by 1/2 billion from BP that results state the oil is going away naturally. Have a bridge in Brooklyn and Swamp in Florida for sale. Anyone buying?
Reply | Report Abuse | Link to this"there will be a lot of dead microbes that will have to be consumed as the next step in the process."
Reply | Report Abuse | Link to thisYou mean like descending to the ocean floor and...wait for it... turning into oil? A process which evidence is beginning to suggest takes a whole lot less time than we used to think. Hmmm. Maybe oil is a renewable resource after all. What fun to imagine environmentalists blowing arteries denying that idea.