ROBERT SIEGEL, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel.
MICHELE NORRIS, host:
And I'm Michele Norris.
And we begin this hour in the air, high above the Gulf of Mexico where it's clear that oil that leaked from the damaged BP well is now dissipating.
A Coast Guard flight over the area shows there's more of what's called oil sheen but fewer of the thick black bands of oil that once marked the site.
As NPR's Jamie Tarabay reports, scientists want to know where the oil has gone now that it's left the surface.
(Soundbite of helicopter)
JAMIE TARABAY: The Houma Jet Center terminal is a revolving door of private planes and helicopters owned by petroleum companies. Every few minutes, someone is taking off. The U.S. Coast Guard took a group of journalists on one of its flyovers to look at the site of the oil spill.
Thom Baugh is a maintenance technician with the Coast Guard.
Mr. THOM BAUGH (Maintenance Technician, U.S. Coast Guard): There's a spot of sheen coming up on the right-hand side. This is Grand Isle area.
TARABAY: About an hour later and a hundred 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. Baugh notes the difference in the texture of the water from 1,200 feet in the air.
Mr. BAUGH: When I flew two weeks ago, there was more oil at that time, there were more streaks of oil. And there was more skimming operations going on.
TARABAY: 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 of more than 4,000 vessels working to stop it being repaired, the oil is dissipating.
Scientists like Ed Overton had been tracking the oil.
Dr. ED OVERTON (Professor Emeritus, Department of Environmental Sciences, School of the Coast & Environment, Louisiana State University): We've been very busy, yes.
TARABAY: Overton, an environmental chemist at Louisiana State University, has been studying oil spills since 1977. Here's what he says is happening beneath the surface.
Dr. OVERTON: The last hundred 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 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.
TARABAY: 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 is then consumed by other organisms.
Dr. OVERTON: It gets eaten by these little critters, those little critters turn into food for the big critters.
TARABAY: And then we eat the fish. Aren't we all ingesting oil in some form?
Dr. OVERTON: It's changed from oil into the life matter of the bacteria. And it's just like when we eat corn on the cob, you don't look like a corn cob.
TARABAY: But it's still unclear how much oil lies beneath the surface. Jane Lubchenco of the National Oceanic Atmospheric Administration 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.
Dr. JANE LUBCHENCO (Administrator, National Oceanographic and Atmospheric Administration): Dilute doesn't mean benign, and we continue to measure where it is and track it and try to understand its impact.
TARABAY: She says little of the oil on the surface is recoverable, so skimming operations have scaled back. But it's not over yet. Lubchenco says more than 600 miles of shoreline has been affected and expects strong winds in the coming days to wash even more oil onshore.
(Soundbite of motor)
Coming off the Coast Guard flight was pilot Lieutenant Commander Dan Lanigan. He says he's encouraged by the difference he's seen in the water.
Lieutenant Commander DAN LANIGAN (Coast Guard): I think we might actually go to the beach this weekend with the family. And I'm really happy to see how it's turning out a lot better than it has been.
TARABAY: He might not, however, get to dip his toes in. Some of the beaches are still closed because of the oil.
Jamie Tarabay, NPR News, New Orleans.
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