CSMonitor: Gulf oil spill: Where has the oil gone?

Since BP capped its ruptured well, the Gulf oil spill has shrunk dramatically. The Gulf itself is breaking down the oil at top speed, but past spills indicate the effects could linger for decades.

By Patrik Jonsson, Staff writer / July 27, 2010

Since BP capped the renegade Macondo well at the center of the Gulf oil disaster 12 days ago, the oil slick has shrunk to about 10,000 square miles from 80,000 square miles in just a matter of weeks.

The reduction has amazed scientists who are tracking the spill and raised many questions about where all the oil has gone. An 800-vessel skimming fleet that weeks ago pulled in 25,000 barrels of oil a day could barely find 50 barrels a day late last week. That means much of the up to 3 million barrels suspected to be remaining in the Gulf has largely gone off the radar.

It’s clear the Gulf is doing what Louisiana State University biologist Ed Overton calls “Mother Nature’s work” in breaking down the patchy oil. Oil-eating bacterial microbes are working at a fast pace. But scientists are still unsure of the longer term environmental impact. Many fishermen are convinced that much of the oil is suspended in the water column or has drifted to the bottom, where it’s impacting oyster beds, crab herds, and spawning fish schools.

“Superficially, everything is going to look fine and within a couple of years we’ll be back to normal shrimp catches, but we will have certain species on which this will have had a catastrophic effect and that will be a long time in recovery,” says Thomas Shirley, a marine biologist at Texas A&M University in Corpus Christi.

The Gulf oil spill is not a containable event like the 1989 Exxon Valdez disaster, which dropped thick sludge in Prince Edward Sound, Alaska. Days after the Deepwater Horizon accident in the Gulf, the government sent skimmers hunting for visible slicks. Boats managed to sop up about 1 million barrels of the estimated 4 million barrels from the ruptured Macondo well, showing how widely the oil has spread.

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