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Ships assist in clean up and containment near the source of the BP Deepwater Horizon oil spill July 27, 2010 in the Gulf of Mexico off the coast of Louisiana.
A recent Coast Guard flight over the site of the exploded BP oil well shows that the thick black swaths of oil have dissipated in the Gulf. It appears that months of skimming, surface burns and other methods of containing the spill are working, and one environmental chemist says under the surface, bacteria are feasting on the oil.
The Coast Guard on Tuesday took journalists on one of its flyovers to look at the site of the oil spill.
About 100 miles from the mouth of the Mississippi, we come upon the oil rigs and supply vessels working where the Deepwater Horizon exploded and sank in April. Thom Baugh, a maintenance technician with the Coast Guard, notes the difference in the texture of the water from 1,200 feet in the air.
"When I flew two weeks ago, there was more oil at that time -- there were more streaks of oil -- and there were more skimming operations going on," Baugh says.
Two months ago, I took a boat ride to this exact spot and it was thick with black oil. The flight this week revealed a dramatic difference. The BP well has been capped for nearly two weeks now, so no new oil has been pouring into the water. Between the skimming, the surface burns and chemical dispersants and the more than 4,000 vessels working to stop it from spreading, the oil is dissipating.
Ed Overton, an environmental chemist at Louisiana State University, has been tracking the oil spill. He has been studying oil spills since 1977. Here's how he explains what is happening beneath the surface.
"Over the last 100 days or so, the natural microorganisms that are out there, that are part of the degradation system. When there's a big oil spill, there's a lot of food, so they multiply and grow. When new fresh oil stopped going into the environment, all of this bacteria is still hungry, so I think the oil is still out there, but it's being degraded very quickly. A massive amount of it has already been degraded."
He says light oil dissolves quicker in the heat -- the Southern summer and the recent storm all helped. And what's left is eaten by the bacteria, which Overton says are then consumed by other organisms.
"It gets eaten by these little critters and those little critters turn into food for the big critters," Overton says.
But since we eat the fish, aren't we then ingesting the oil in some form?
"It's changed from oil into the life matter of bacteria," Overton says. "It's just like when we eat corn on the cob, you don't look like a corn cob."
But it's still unclear how much oil lies beneath the surface. Jane Lubchenco of the National Oceanic Atmospheric Association makes a point that the oil is not on the seabed, it's in the water column, and much of that is in microscopic droplets in dilute concentrations.
"Dilute doesn't mean benign, and we continue to measure where it is and track it and try to understand its impact," Lubchenco says.
She says little of the oil on the surface is recoverable, so skimming operations have scaled back. But it's not over yet. Lubchencko says more than 600 miles of shoreline has been affected, and she expects strong winds in the coming days to wash even more oil onshore.
After seeing the Gulf on the July 27 Coast Guard flight, Lt. Commander Dan Lanigan says he's encouraged by the difference he's seen in the water.
"I think we might actually go to the beach this weekend with the family. I'm really happy to see how it's turning out a lot better than it's been," Lanigan says.
He might not, however, get to dip his toes in. Some of the beaches are closed because of the oil. Copyright 2010 National Public Radio. To see more, visit http://www.npr.org/.