ROBERT SIEGEL, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel.
The U.S. government has said that most of the oil that spewed into the Gulf of Mexico from BP's ruptured well is no longer in the water. But a group of scientists now says, not so fast. Instead, they insist three-quarters of the oil or more is still likely in the Gulf, much of it lurking far below the surface.
NPR's Elizabeth Shogren has our story.
ELIZABETH SHOGREN: The federal government said the vast majority of oil had evaporated, been captured, vacuumed up, burned or dispersed. And much of what was left was being degraded. Some scientists couldn't believe what they were reading.
Professor CHUCK HOPKINSON (Marine Science, University of Georgia): We saw some press reports that 75 percent of the oil was gone and we were alarmed at hearing that number.
SHOGREN: Chuck Hopkinson directs the Georgia Sea Grant. He believes those reports gave the public an absolutely incorrect impression, which the government failed to contradict. He gathered a group of scientists who came up with a radically different assessment. University of Georgia marine scientist Samantha Joye was part of that team.
Professor SAMANTHA JOYE (Marine Scientist, University of Georgia): Now, if you use conservative numbers, then you come up with 70 to 80 percent of the oil still out there, not 75 percent is gone.
SHOGREN: Joye worries that a perception that most of the BP oil is gone could undercut the massive effort that is still needed to track down the facts.
Prof. JOYE: There's oil in the water. There's oil on the sea floor. There are going to be impacts to the system. If we assume that there is no longer a problem and we stop making measurements, then there are going to be a lot of unknowns.
Ms. JANE LUBCHENCO (Administrator, NOAA): I have great respect for the Georgia scientists, but I think the report that they issued is actually puzzling and confusing.
SHOGREN: Jane Lubchenco heads the NOAA, the National Oceanic and Atmospheric Administration. She's the lead author of the government study. Lubchenco says the Georgia scientists didn't include in their calculations oil from the well that was captured before it got into the Gulf.
Ms. LUBCHENCO: It's hard to compare one to the other when you have different starting numbers. It's comparing apples and oranges. And it skews the numbers upwards.
SHOGREN: But that's not the only major difference. The government estimates that a quarter of the BP oil evaporated. The Georgia scientists argue that much less did. Lubchenco stands by her estimate. She says it comes from experts inside and outside of government who understand the particular chemistry of the light petroleum that spewed from the well.
But Hopkinson from Georgia Sea Grant, which is a NOAA funded program, says his team believes much of the oil was trapped in (unintelligible) deep underwater so it couldn't evaporate.
Prof. HOPKINSON: To evaporate, it has to rise to the surface and have contact with the atmosphere. Because so much of the oil is at deeper depths, we didn't think it was realistic to assume that the entire volume evaporated.
SHOGREN: Louisiana State University environmental scientist Edward Overton says the government and the Georgia scientists are basing their reports on educated guesses.
Professor EDWARD OVERTON (Environmental Scientist, Louisiana State University): All of these are based on very little actual data. The bottom line is that we really don't know how much oil is left out there.
SHOGREN: Overton is making his own educated guesses and believes that both the government and the Georgia scientists are underestimating how much oil has evaporated. But he thinks there's a lot of room for knowledgeable scientists to disagree.
Prof. OVERTON: We won't know whos right for some time yet because we've got to go out and do the analysis down in the deep oceans and try to find the oil, see if it's there, see how quickly it's degrading. And all of that takes times.
SHOGREN: In fact, Overton says, we may never know, because much of the data may be impossible to recover. Still, all the scientists agree that the tremendous amount of oil that spewed into the Gulf has done and will do serious harm to marine life.
Elizabeth Shogren, NPR News.
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