Thank dilution and the Gulf Stream for keeping oil away
The oil that continues to spill into the Gulf of Mexico is unlikely to wash up on Georgia’s shores, researchers at Skidaway Institute of Oceanography say.
National Oceanic and Atmospheric Administration officials warned earlier this week oil from the BP spill could be entering the loop current in the Gulf. That would give it a free ride around Florida and up the East Coast as the loop current feeds into the Gulf Stream.
But several features of Georgia’s coast are keeping associate professor Dana Savidge optimistic about avoiding tar balls at Tybee and oil sheens in Skidaway marshes.
For one, the Gulf Stream current is far offshore here, about 70 miles out. That northerly flow of deep, warm water sits at the edge of our continental shelf, which is wider here than anywhere south of Martha’s Vineyard.
There’s some evidence of transport between the Gulf Stream and the shallow shelf waters. Witness the sargussum seaweed that sometimes washes inshore.
But there’s also reassurance in the observation that the Gulf Stream usually keeps to itself. When researchers release drifters – floating objects tracked by satellite – they routinely fail to pop out of the Gulf Stream and cross the continental shelf off Georgia, Savidge said.
Then there’s the historical record.
Dick Lee, a professor emeritus at Skidaway Institute, looked for effects on Georgia of the last major oil spill in the Gulf, in 1979. That was the Ixtoc I oil well blowout west of the Yucatan that spewed about 20,000 barrels a day into the Gulf for eight months. Oil did enter the loop current, but when Lee and a colleague surveyed for it in the Gulf Stream off Georgia months later, they found no increase in the number of tar balls their tows captured.
“Every tow had some tar balls in it,” he said. “It always will from traffic in the world’s ocean, from natural seeps and whatnot. But we didn’t see any increase in tar balls.”
The Gulf Stream moves at about 1 mph, Savidge said. Once oil enters the loop current, it would take about two weeks to reach offshore Georgia. Much of the oil will evaporate, be degraded by sunlight or consumed by oil-eating microbes before it gets here.
The warm waters and intense sunshine of the Gulf of Mexico and the Atlantic Ocean make those processes more effective than they were during the Exxon Valdez spill.
The oil will also be transformed by dilution and mixing with saltwater to become tar balls and denser oil-saltwater mixtures, which may not all be at the surface.
“The lifetime of these tar balls is about a year,” Savidge said.
Both Savidge and Lee admit there are a lot of unknowns in predicting where this oil will go.
The uncertainty is keeping the Georgia Department of Natural Resources on alert about the spill. Spud Woodward, director of the Coastal Resources Division, said he’d be surprised to see oil here, but he’s had preliminary talks with the Coast Guard about how the state would respond.
“I think it’s still a long shot,” he said. “You’d have to have a large amount of oil entrained in the loop. And its arrival would have to be simultaneous with a weather event with a strong easterly wind. I’m not going to say it can’t happen. Strange things happen.”
Similarly, Terry Norton, the director and veterinarian at the Georgia Sea Turtle Center on Jekyll Island, said he hasn’t treated any oil-affected turtles yet, but is bracing for patients from the spill, likely from Florida. He may eventually be treating turtles with chronic toxicity from eating oil-fouled crabs and fish.
“I think the spill will have a huge impact on wildlife,” he said. “But I don’t know about in Georgia.”
Hatchling loggerhead sea turtles from Georgia beaches make their way to the Gulf Stream and ride it for years, Norton said. How the spill will affect them will be difficult to judge.
“They float around on that current for 10-12 years,” Norton said. “Those stages could be heavily impacted, and we wouldn’t know it.”
Local pets and their people contributed 129 pounds of fur and hair to the Gulf Coast oil cleanup.
The hair and fur, collected from area groomers and hair salons, is on its way to a Pensacola, Fla., warehouse, said Lisa Scarbrough, who organized the local effort.
The idea behind the collection is to have fur woven into mats or stuffed into donated nylons to create oil booms.
Oil clings to hair or fur. That fact, combined with the huge quantities of hair thrown away every day in the U.S. sparked the nonprofit Matter of Trust organization to start collecting hair and fur for oil boom creation 10 years ago. The California-based group stepped up its efforts in response to the Gulf spill.
It’s a little unclear whether the fur booms are being deployed. BP initially declined to use them, Scarbrough said. Then, after public outcry, the company may have reconsidered. Matter of Trust’s website posted an announcement Thursday that BP had contacted the group, presumably about using the booms. But the promised update and press release hadn’t materialized by Friday afternoon.
Scarbrough, the founder of Coastal Pet Rescue, read about the need for donated fur and mobilized local businesses to collect it after researching the issue.
“I’m pretty confident some of it will be used if not all of it,” she said. “Whether it’s BP or local agencies, it’s a great resource.”
Some of the donated fur came from groomers. Other donors gave boxes and shipping funds; still others served as drop-off locations. Businesses participating included Hoof and Woof, Animal Resort and Spa, Islands Pet Center, Diva Dogs, Paws Doggy Day Spa & Grooming by Sonia, Case Veterinary Hospital, Top Dog Spa, New Attitudes Hair Studio, Dr. Nancy M. Eschette, Catnip N Biscuits, Seaside Sisters, and Paula Deen Enterprises.
The fur, enough to fill Coastal Pet Rescue’s SUV, was collected in two weeks.
“I really had no idea just how supportive the community would be for such an unusual effort,” Scarbrough said.
Source: http://savannahnow.com/news/2010-05-22/gulf-spill-unlikely-mar-georgias-shores