By David Gura

Authorities say tar balls, discovered on the Florida Keys, are being tested to determine if the pollution is the result of BP's massive oil spill in the Gulf of Mexico. Oceanographers at the University of South Florida (USF) are concerned that the oil has reached the so-called Loop Current, which could carry it to the East Coast, NPR's Debbie Elliott reports from Orange Beach, Fla.

According to the Ocean Circulation Group at USF, "forecasts say -- assuming persistence of the Loop Current and absent significant dispersion and evaporation of the oil -- the slick may reach the middle Keys in the Florida Straight by May 26.

NPR's Elizabeth Shogren, reporting from New Orleans, says that the government is worried that fragile mangroves and marine animals far from the BP accident could now be threatened.

NOAA Administrator Jane Lubchenco says that aerial surveys show the main oil slick is dozens of miles from the Loop Current, which circulates water to the Florida Keys, and then to the Gulf Stream in the Atlantic Ocean. But, she adds, "a tendril of light oil has been transported down to the Loop Current."

NOAA will try to determine if the oil is in the current, moving toward South Florida. It expanded the area of the Gulf of Mexico closed to fishing today, to cover 19 percent of federal waters in the Gulf, from Louisiana to Northwest Florida.

categories: Environment

12:58 - May 18, 2010