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At depths of 900 to 3,300 feet, the University of South Florida researchers found problems with plant plankton. About two-fifths of the samples showed "some degree of toxicity."
"We found general phytoplankton health to be poor," Hollander said. By comparison, in non-oiled southern parts of the Gulf, the plant plankton were healthy, researchers said.
That makes sense because past research has shown that when oil when gets into the cell membranes of plankton, it causes all sorts of problems, said Paul Falkowski, a marine scientist at Rutgers University who was not part of the research. However, he said plant plankton don't live long anyway. They have about a week's lifespan, he said, and in a few months this insult to the base of the food web could be history.
Still, the brew that is poisoning the plankton may linger and no one knows for how long, Hollander said.
The Florida researchers used ultraviolet light to illuminate micro-droplets of oil deep underwater. When they did that, "it looked like a constellation of stars," Hollander said.
He also found the oil deposited in the sea bottom near the edges of the significant DeSoto Canyon, about 40 miles southwest of Panama City, Fla., suggesting oil may have settled into that canyon. The canyon is an important mixing area for cold, nutrient-laden water and warmer surface water. It is also key for currents and an important fisheries area.
"Clearly the oil down in the abyss, there's nothing we can do about it," said Ed Overton of Louisiana State University. He said the environment at the surface or down to 100 feet or so is "rapidly going back to normal," with shrimpers starting their harvest. But oil below 1,000 feet degrades much more slowly, he said.
Joye has measured how fast natural gas, which also spewed from the BP well, can degrade in water, and it may take as much as 500 days for large pools to disappear at 3,000 feet below the sea. That natural gas starves oxygen from the water, she said.
"You're talking about a best-case situation of a year's turnover time," Joye said.
___
Online:
University of Georgia's oil spill page:
http://oilspill.uga.edu/
[Associated
Press;
Copyright 2010 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
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