BATON ROUGE, La.
Laboratory tests confirmed that oil from a spewing Gulf of Mexico well has accumulated in at least two extensive plumes deep under the surface, scientists with the University of South Florida said Friday.
USF researchers at a meeting in Baton Rouge said lab tests showed their initial findings, based on field instruments, were correct. The extensive layers of oil are sitting far beneath the surface miles from the site of the Deepwater Horizon explosion. The university is collecting data for the National Oceanic and Atmospheric Administration.
The lab tests are the most conclusive evidence yet in a vigorous scientific debate about where much of the oil from the growing spill in the Gulf of Mexico has ended up.
BP spokesman Mark Proelger said the company was awaiting further analysis of what is in the plumes from the National Oceanic and Atmospheric Administration.
"It's too early to say whether any data indicates the plumes contain oil or not," Proelger said.
During its own testing of waters around the spill site between May 7 and May 26, BP found evidence of oil in samples taken from more than two dozen locations. However, none of the sites revealed oil concentrations greater than 75 parts per billion. "These very low concentrations do not have a significant effect on marine life," the company said in a May 30 report to the federal government.
Fish toxicologists say thick plumes of oil can kill off adult fish and their eggs by exposing them to high concentrations of potent toxins. But even at very low concentrations, the combination of oil and dispersants -- which have been used in large volumes on the Gulf spill -- increases the potential for small marine creatures to be poisoned.
USF and NOAA planned to issue a more full report on their findings about the oil plumes Monday.
"We're certain it's oil," said Ernst B. Peebles, a USF biological oceanographer and chief scientist aboard the college's Weatherbird II research vessel, the ship that did the sampling. "We've done the analysis."
Peebles said laboratory tests were performed on water drawn from two layers of oil, a 98-foot thick layer found about 1,300 feet down and a second, even thicker layer found at a depth of about 3,200 feet.
The tests were performed on water brought up by collection bottles and passed through filter pads, a web of glass fibers that trap tiny particles in water.
William T. Hogarth, the dean of USF's College of Marine Science and a fishery biologist, said it was too early to say whether the underwater oil posed a serious threat to the Gulf's ecosystem.
Still, he was concerned.
"If you look back at Alaska, the herring population in Alaska is still impacted," he said, referring to the Exxon Valdez spill in the Prince William Sound in Alaska. "We've found oil in the water column, the next step is to test fish, test the plankton, to determine the mortality, to determine what the ramifications are."
Jane Lubchenco, under secretary of commerce for oceans and atmosphere and National Oceanic and Atmospheric Administration, said the agency was deeply concerned about the effects of the oil to Gulf fisheries, the ecosystem and coastal communities.
"We know there is oil below the surface. The questions are where is it, in what concentrations, and where is it going. That is what NOAA scientists and our academic partners, deployed on ships throughout the Gulf, are determined to discover," Lubchenco said.
Chris D'Elia, the dean of LSU's School of Energy, Coast and Environment, said NOAA Administrator Jane Lubchenco told scientists in Baton Rouge on Thursday that the oil under the water "did not look like they were in great concentrations."
Scientists are worried, though. In the Gulf, the Atlantic bluefin tuna is at risk because they spawn almost exclusively in parts of the Gulf, including the region around the Deepwater Horizon spill, said Peter Hodson, a fish toxicologist at Queen's University in Kingston, Ontario.
Hodson said the tuna's free-floating eggs can be killed at levels as low as one part per million, meaning a gallon of oil for every million gallons of water.
"You can wipe out reproduction," Hodson said. He added that could "have an ocean-wide impact" since tuna depart the Gulf in late summer to spread out across the Atlantic.
Hogarth said NOAA was analyzing the concentrations of oil.
Peebles talked about the lab tests at a meeting at Louisiana State University where BP and academics discussed how to spend $500 million BP has agreed to pay to study the effects of the Gulf spill.
Associated Press writer Matthew Brown in Billings, Mont., contributed to this report.