|Oil slick in the Gulf of Mexico.|
Scientist locates another vast oil plume in the gulfMay 28, 2010
A day after scientists reported finding a huge "plume" of oil extending miles east of the leaking BP well, on Friday a Louisiana scientist said his crew had located another vast plume of oily globs, miles in the opposite direction.
James H. Cowan Jr., a professor at Louisiana State University, said his crew on Wednesday found a plume of oil in a section of the gulf 75 miles northwest of the source of the leak.
Cowan said that his crew sent a remotely controlled submarine into the water, and found it full of oily globules, from the size of a thumbnail to the size of a golf ball. Unlike the plume found east of the leak -- in which the oil was so dissolved that contaminated water appeared clear -- Cowan said the oil at this site was so thick that it covered the lights on the submarine.
"It almost looks like big wet snowflakes, but they're brown and black and oily," Cowan said. The submarine returned to the surface entirely black, he said.
Cowan said that the submarine traveled about 400 feet down, close to the sea floor, and found oil all the way down. Trying to find the edges of the plume, he said the submarine traveled miles from side to side.
"We really never found either end of it," he said. He said he did not know how wide the plume actually was, or how far it stretched away to the west. He said the plume was found in an area that had already been closed to fishing by the federal government.
Cowan's finding underscores concerns about oil moving under the surface, perhaps because of dispersant chemicals that have broken it up into smaller globules. BP officials have played down the possibility of undersea oil plumes.
This discovery seems to confirm the fears of some scientists that -- because of the depth of the leak and the heavy use of chemical "dispersants" -- this spill was behaving differently than others. Instead of floating on top of the water, it may be moving beneath it.
That would be troubling because it could mean the oil would slip past coastal defenses such as "containment booms" designed to stop it on the surface. Already, scientists and officials in Louisiana have reported finding thick oil washing ashore despite the presence of floating booms.
It would also be a problem for hidden ecosystems deep under the gulf. There, scientists say, the oil could be absorbed by tiny animals and enter a food chain that builds to large, beloved sport-fish like red snapper. It might also glom on to deep-water coral formations, and cover the small animals that make up each piece of coral.
"You're almost like a deer in the headlights when you're watching this. You don't know what to say," Cowan said. He said the oil's threat to undersea ecosystems "is really starting to scare us."
In the discovery described Thursday, scientists aboard a University of South Florida research vessel found an area of dissolved oil east of the leak that is about six miles wide, and extends from the surface down to a depth of about 3,200 feet, said Professor David Hollander.
Hollander said that he believed the plume might have stretched more than 20 miles from the site of a leak on the floor of the Gulf of Mexico, where the Deepwater Horizon drilling rig sank April 22. It has not yet reached Florida.
The plume is clear, with the oil entirely dissolved.
"Here is a situation where, unless you're looking at the chemical fingerprints, [the oil] is absolutely not visible," Hollander said. "It's not some Italian vinaigrette or anything like that. It's absolutely, perfectly clear."
But, Hollander said, even this clear-looking water could contain enough oil to be toxic to small animals at the base of the gulf food chain. He said he was also worried that the oil contains traces of "dispersants," soaplike chemicals sprayed into the oil to break it up.
"You don't want to put soap into a fish tank," Hollander said.
The University of South Florida vessel, the Weatherbird II, used sonar and other devices to sample the water below it. Other scientists have said they have little of the equipment necessary to find oil under the water, leading to debates about whether the underwater plumes were even there.
This week, Mike Utsler, who helps oversee the spill response off the entire Louisiana coast as BP Houma incident commander, said he's focused only on taking oil off the surface. "We don't know there's oil underwater," he said.
William Hogarth, dean of the USF College of Marine Science, said university researchers have sent samples to federal officials for analysis, but it's clear the oil is new because Stanford scientists had sampled the same area a year ago and found no evidence of oil. The Weatherbird II will conduct another tour next week, he said, with different researchers aboard.
"This is not natural seep," he said, adding that scientists will have to study the region for several years in order to properly gauge its impact. "We're talking about probably a three-to-five-year monitoring program to see what happens to food chain."