USF researchers find second oil plume

The discovery in the depths of the Gulf of Mexico was so unsettling University of South Florida marine scientists ran two tests this week just to make sure.

Data from an array of instruments was conclusive: a team on board the USF research vessel Weatherbird II had discovered a vast new plume of oil about 3,300 feet beneath the waves.

The blob, more than 6 miles wide, is stretching inland toward the shallower waters off Alabama, where many fish and other species reproduce, said David Hollander, associate professor of chemical oceanography at USF.

"The first ecological impact of this spill is the effect on coastal habitats, including marshes, beaches and estuaries," Hollander said. "The second threat to nature would be the impact on the food webs. That is what's at risk."

The National Oceanographic and Atmospheric Administration said Thursday that computer models showed oil from the spill was about 75 miles southwest of Pensacola and 305 miles from Clearwater.

The first plume detected by scientists after the offshore rig Deepwater Horizon exploded on April 20 flowed southwest to the open sea from the gushing well 5,000 feet below the surface.

For weeks, scientists with various agencies have been trying to determine the size and amount of the ooze in deep water. Satellite imagery only shows oil on the surface.

The team on the Weatherbird II detected the thickest amount of hydrocarbons, likely from the oil spewing from the blown-out well, at about 1,300 feet in the same spot on Tuesday and again on Wednesday.

Repeating the tests proved that the substance found in the water was not naturally occurring and that the plume was at its highest concentration in deeper waters, Hollander said.

Scientists need to do more tests to determine whether those hydrocarbons are from the 850,000 gallons of chemical dispersants used to break up the ooze or the emulsification of oil as it flowed away from the gushing well.

The research team also discovered no oil had been pulled into an unpredictable current that could have brought slicks and tar balls to West Florida shores.

Samples of water taken from the so-called loop current showed that there was no weathered oil on the surface or plumes of oil in the deep water dragged into the eddy. On Tuesday, scientists with NOAA said the loop current has split in half, diminishing the threat to Florida.

The current moves and grows in size every few days, USF oceanographers said. Typically, the U-shaped current surges north before turning south toward the Florida Keys. From there, it joins with the powerful Gulf Stream and swings north along the east coast of the United States.