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Hardy bugs are eating up the mess

POSTED August 31, 2010 9:20 p.m.

The disaster in the Gulf has been plenty grim. I don’t envy paymaster Kenneth Feinberg who has now taken over BP’s $20 billion compensation fund. Feinberg is no stranger to trying to compensate those who have lost much, including the families affected by Sept. 11, 2001, and a somewhat lower-profile project to compensate victims of the shootings at Virginia Tech.

But the magnitude and complexity of the Gulf disaster is second to none. From what I can see, there’s just no good way to distribute the money to those who have lost so much in different ways in various places.

Still, there’s some good news. Since petroleum stopped flowing from the Deepwater Horizon site, oil at the surface has been harder and harder to find. And microorganisms look to some scientists as if they may be poised to eat up a lot of the underwater oil quite quickly.

According to ScienceNOW, the first peer-reviewed study to come out of the Gulf indicated the natural oil-loving “bugs” weren’t doing as much as might be hoped. But the second one published last week looked at the microbes themselves and found much more reason to be optimistic.

Some bacteria in the seas have evolved over time to make a living on the seepage of oil that has always occurred naturally on the sea floor. The ScienceNOW website quotes NOAA marine ecologist Alan Mearns on the matter. “With all of the seepage, including the 40 to 50 million gallons a year that seep naturally into the Gulf, we’d have oceans covered with oil slicks if they weren’t naturally degrading,” Mearns said.

The bacteria in question consume hydrocarbons and oxygen, producing carbon dioxide as waste. The most recent study is based on samples of ocean water from a depth of more than 3000 feet, both in an oil plume and outside it. The good news is that the study reports the concentration of the bugs inside the plume is twice as dense in the water as outside it. And the bugs in the plume have more of the genes needed to eat up the oil.

It’s still an open question exactly at exactly what rate the bugs are consuming the oil in the underwater plumes. Crude oil is a complex soup, made of many different types of molecules. The encouraging study concentrated on the alkanes, a type of molecule that’s generally among the first to naturally degrade.

Another factor is that the petroleum mixes with water in complex ways. The term for the globs of oil in the water you’ve seen in the news is “emulsion.” Emulsions are what results when two liquids that won’t mix in chemical terms are physically blended together. You make an emulsion each time you shake up vinaigrette salad dressing, blending the oil and vinegar. Homogenized milk is a mix of fat and water so thoroughly emulsified that it’s permanently mixed together, with no separation down the road as in the vinaigrette case.

In the Gulf of Mexico, crude oil and seawater have been mixed together in a messy emulsion in the weeks following the disaster. What we don’t know is how readily the globs of the emulsion will now break apart. We should keep our fingers crossed that they do so, because smaller and smaller bits of oil will give the bacteria a greater chance of being able to quickly eat up the crude.

One worry has been that, as the microbes in the Gulf go to work, they might use up the oxygen in the waters around them. That would create a “dead zone,” like having too much fertilizer escape into waters with resultant algal blooms. Dead zones in the Gulf would be disastrous for fish that blundered into them. But the two scientific reports to date don’t show that the oxygen has fallen to dangerous levels.

Considering the magnitude of the spill, the current scientific news from the Gulf is really quite good. Marine ecologist Mearns is hopeful that the oil plumes will be gone quickly.

“We’re talking days to months,” he said.

But I suspect Feinberg’s headaches are only beginning.

 

— Dr. E. Kirsten Peters, a native of the rural Northwest, was trained as a geologist at Princeton and Harvard. Questions about science or energy for future Rock Docs can be sent to epeters@wsu.edu. This column is a service of the College of Agricultural, Human, and Natural Resource Sciences at Washington State University.

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