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.
Perhaps the most important cause of the oilís disappearance
, some researchers suspect, is that the oil has been devoured by microbes
. The lesson from past spills is that the lionís 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
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
ó and spilling lots of it ó 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, thatís evidence that the microbes are hard at work
Mighty oil-eating microbes help clean up the Gulf - Yahoo! News