Gulf Oil Spill: Will Undersea Plumes Create Dead Zones?


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"BP’s sampling of the water showed 'no evidence' that oil was
suspended beneath the surface."

BP’s Chief Executive Officer Tony Hayward

The BP oil spill in the Gulf of Mexico may soon create undersea oxygen-depleting dead zones  killing sea life and upsetting the region’s ecology for decades, scientists say.

Microbes in the sea that feed on oil seeping from the seafloor may consume most of the underwater oil from the leak, according to
Frank Muller-Karger, professor of biological oceanography at the
University of South Florida. But populations of oil-gorged microbes
could expand rapidly, consuming oxygen needed by other sea life and
creating “dead zones.”

Tony Hayward, CEO of BP, says oil is only on the Gulf's surface and samples from company scientists say there's no evidence oil has sunk below the waves. Researchers at several universities – including USF's College of Marine Science – have reported layers of oil are reaching deep under water.

James Cowan, a marine scientist from Lousiana State University, told the Associated Press his reaction to BP's comments.

"To me, I just don't think that Mr. Hayward has spent much time looking for it," Cowan said. "And I certainly don't think he wants to find it, because it would make cleanup efforts much more complicated if there is oil suspended at depth."

And at least one congressman is questioning BP's claims. Massachusetts Democrat Edward Markey has sent a letter to Hayward, asking for documents to back up his claims. Markey says the government and researchers need to have unfettered access to all the company's data on the underwater plumes.

Also, a group of academicians will meet Wednesday for the first time in St. Petersburg to discuss their reaction to the Gulf oil spill.

It's called the Oil Spill Academic Task Force. It's made up of scientists from throughout the state's university system – as well as private colleges. It was created by the Florida Board of Governors, which oversees public universities, to coordinate research on the Gulf oil spill.

The universities have been in the forefront of research in to the extent of the oil spill, it's possible trajectory and how deep the oil can be found. They rely on data from automated underwater gliders, as well as the research vessels based in St. Petersburg. 

“You end up with a transformation of the chemistry of the water, and we are not clear on what that is,” Muller- Karger said in an interview with Business Week's Jessica Resnick-Ault referring to the undersea spillage..

Oil from
the spill may have spread underwater for 22 miles toward Mobile,
Alabama, researchers aboard a University of South Florida vessel
reported May 27. Initial tests aboard the Weatherbird II show the
highest concentrations of “dissolved hydrocarbons” were 1,312 feet (400
meters) below the surface.

“There is great, great concern of the subsurface nature of this event, of the amount of dispersants and what this means to the entire ecosystem,” Roger Helm, Chief of the U.S. Fish and Wildlife Service Division of Environmental Quality, said at a press conference. “This is going to be groundbreaking science.”

A government team appointed by the Coast Guard estimates oil has been spilling from the well at a rate of 12,000 to 19,000 barrels a day. That could increase as much as 20 percent when BP makes its next attempt to control the leak by sawing off a damaged pipe. Within the week, BP plans to reconnect the pipe and funnel oil to a ship on the surface.

Even if BP succeeds, “This much oil in a productive marine environment will cause substantial environmental damage,” said Rick Steiner, a marine biologist and consultant who has worked with governments and the United Nations on oil spills.

Marine biologists are worried the oil will kill off fragile organisms, such as shrimp and fish larvae and plankton, a critical part of the offshore food chain, Steiner said. Fish can also suffocate if their gills are coated with crude.

Research crews dispatched to study the spill include expeditions funded by the Louisiana Universities Marine Consortium, the National Oceanic and Atmospheric Administration, and the National Science Foundation.

As of yesterday, the Unified Area Command in Robert, Louisiana, reported oil along 100 miles of Louisiana coastline. Nearly 100 birds and five sea turtles have been found dead or visibly oiled, according to the Command’s latest report. Hundreds more birds and turtles may have been affected, the report says.

Coastal marshlands, which are breeding grounds for a rich variety of sea life, will take years to recover from the toxic effects of crude, scientists say.

The environmental effects of oil spreading beneath the sea are less certain.

“We are now entering a different phase of this disaster,” said Samantha Joye, a researcher at the University of Georgia who is part of a group gathering data about the spill.

“Everybody has been focusing on the surface impacts, which is normal, but now we’ve got to switch gears and start thinking about the deep water,” said Joye, before setting out on a new research mission funded by the National Science Foundation.

Joye’s latest expedition is studying an area of subsea oil estimated to be 15 miles long, 5 miles wide and 300 feet thick. Samples of water taken from deep within the Gulf smelled of crude, Joye wrote in a blog of her trip.

Scientists are packing their research vessels with an arsenal of tools, some of which have never been used in oil spills before. They’ve dragged a “Sipper” — a cross between a microscope and digital camera — behind a boat to collect images of the water.

Boats also carry instruments to measure dissolved hydrocarbons in the water, evaluate water quality at different depths, and detect dissolved organic matter to show whether the ecosystem is changing.

The NOAA research vessel Gordon Gunter is equipped with a special net that can catch fish larvae at different depths to measure the spill’s impact, the agency said in a release May 28. The Gunter will use sonar to search for oil plumes beneath the ocean and has a robotic vehicle, known as the Gulper, to take water samples at distinct depths for study by scientists.

Deep undersea clouds of oil-contaminated water may threaten fish that are migrating through the area. As the Northern Gulf of Mexico warms, bluefin tuna, kingfish, and marlin swim from the Atlantic into the Gulf, said Muller-Karger, of the University of South Florida. Sea turtles, whale sharks, and others follow the same migratory path.

Casey Kazan 

Sources:

http://www.wusf.usf.edu/news/2010/06/01/waves_of_dispute_over_extent_of_gulf_oil_plume and  Business Week, Jessica Resnick-Ault

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