Experts Say

Satellite pictures show oil snared by an eddy.

Satellite pictures show the Gulf oil spill moving toward the Loop Current, which is illustrated at bottom.

Top and middle images courtesy MODIS/NASA; diagram courtesy FGBNMS/NOAA

Christine Dell'Amore

National Geographic News

Published May 18, 2010

Some oil from the Gulf of Mexico spill is "increasingly likely" to be dragged into a strong current that hugs Florida's coasts, National Oceanic and Atmospheric Administration (NOAA) officials said today.

But other experts say that the oil is already there—satellite images show oil caught up in one of the eddies, or powerful whorls, attached to the Loop Current, a high-speed stream that pulses north into the Gulf of Mexico and travels in a clockwise pattern toward Florida.

Images from the past few days show a "big, wide tongue" of oil reaching south from the main area of the spill, off the coast of Louisiana, said Nan Walker, director of Louisiana State University's Earth Scan Laboratory, in the School of the Coast and Environment.

Meanwhile, a particular eddy has intensified and expanded north in recent days. The images reveal that the eddy has snagged oil and pulled it southeastward 100 miles (about 160 kilometers), which means the crude is now circulating inside the turbulent waters.

The oil has also reached the point where the eddy connects to the Loop Current, Walker said. That means the oil is traveling eastward alongside the main stream of the Loop Current, and it's likely that it will continue flowing with the current to Florida, Walker said.

Mitchell Roffer, president of Roffer's Ocean Fishing Forecasting Service in West Melbourne, Florida, has also been tracking the oil spill by satellite.

"Several scientists from different organizations have seen the oil in the Loop Current" via "clear and dramatic" satellite pictures, Roffer said.

"Nowhere to Go But On the Beach"

According to Roffer, the northeast portion of the Loop Current has been moving eastward, closer to Tampa, on Florida's western coast (map). That means if an eddy sweeps the oil into the main current, it has "nowhere to go but on the beach," Roffer said.

Once in the Loop Current, oil can travel south and enter the Gulf Stream, a powerful ocean conveyor belt that carries warm water up the eastern seaboard.

Oil brought to Florida's east coast could then get pulled into inlets and harbors, where it would settle into the mangrove forests that are nurseries for many species of sea life, Roffer pointed out in early May. (See pictures of ten oil-threatened animals.)

On Monday the Coast Guard reported the discovery of 20 tar balls at Key West's Fort Zachary Taylor State Park. The sticky balls of congealed oil are currently being analyzed to determine if they came from the Gulf spill. (See pictures of tar balls and dead dolphins that washed up on Alabama beaches.)

But Roffer said it's unlikely that oil-contaminated Loop Current waters could have reached Key West in that short amount of time.

The current travels about 50 to 100 miles (80 to 160 kilometers) a day, so it would take roughly 13 days or more for oil to get from the site of the damaged Deepwater Horizon rig to Key West, LSU's Walker said.

Oil Lies Beneath?

Researchers from the University of South Florida will venture into the Loop Current via boats later this week to collect water samples and verify the oil's presence, according to the Associated Press.

Such testing is "absolutely" necessary, Roffer said, as is figuring out how much oil lies beneath the water's surface—something satellites can't show.

What the satellite pictures definitely reveal, he said, is that the time for modeling whether oil might get into the Loop Current is over.

"It's not a matter of predicting if it's going to be there or not," Roffer said. "It's there."

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