The Associated Press reported yesterday that only two weeks after BP finally put an end to what seemed like an impossible oil gusher, most of the oil seems to have…disappeared.
So where did the oil go? “Some of the oil evaporates,” explains Edward Bouwer, professor of environmental engineering at Johns Hopkins University. That’s especially true for the more toxic components of oil, which tend to be very volatile, he says. Jeffrey W. Short, a scientist with the environmental group Oceana, told the New York Times that as much as 40 percent of the oil might have evaporated when it reached the surface. High winds from two recent storms may have speeded the evaporation process.
Although there were more than 4,000 boats involved in the skimming operations, those cleanup crews may have only picked up a small percentage of the oil so far. That’s not unusual; in previous oil spills, crews could only scoop up a small amount of oil. “It’s very unusual to get more than 1 or 2 percent,” says Cornell University ecologist Richard Howarth, who worked on the Exxon Valdez spill. Skimming operations will continue in the Gulf for several weeks.
Some of the oil has sunk into the sediments on the ocean floor. Researchers say that’s where the spill could do the most damage. But according to a report in Wednesday’s New York Times, “federal scientists [have determined] the oil [is] primarily sitting in the water column and not on the sea floor.”
Perhaps the most important cause of the oil’s disappearance, some researchers suspect, is that the oil has been devoured by microbes. The lesson from past spills is that the lion’s share of the cleanup work is done by nature in the form of oil-eating bacteria and fungi. The microbes break down the hydrocarbons in oil to use as fuel to grow and reproduce. A bit of oil in the water is like a feeding frenzy, causing microbial populations to grow exponentially.
So, if I’m getting this right, it sounds like they’re saying that nature has an automatic way to compensate for spilled oil. Which, if you think about it, kind of makes sense: the oil is naturally occurring down there. It’s not like BP put a bunch of oil under the ocean floor and spilled it in the process. They were just extracting what’s already there. Apparently, that fact is not lost on some scientists, who posit a theory on the microbial activity in places like the Gulf:
Typically, there are enough microbes in the ocean to consume half of any oil spilled in a month or two, says Howarth. Such microbes have been found in every ocean of the world sampled, from the Arctic to Antarctica. But there are reasons to think that the process may occur more quickly in the Gulf than in other oceans.
Microbes grow faster in the warmer water of the Gulf than they do in, say, the cool waters off Alaska, where the Exxon Valdez spill occurred. Moreover, the Gulf is hardly pristine. Even before humans started drilling for oil in the Gulf — and spilling lots of it — oil naturally seeped into the water. As a result, the Gulf evolved a rich collection of petroleum-loving microbes, ready to pounce on any new spill. The microbes are clever and tough, observes Samantha Joye, microbial geochemist at the University of Georgia. Joye has shown that oxygen levels in parts of the Gulf contaminated with oil have dropped. Since microbes need oxygen to eat the petroleum, that’s evidence that the microbes are hard at work.
If I wasn’t enlightened enough to know better, it would almost seem that the ocean had been designed to work this way.