The current is a powerful conveyor belt of water that flows around the gulf toward Florida.
"With these images from space, we have visible proof that at least oil from the surface of the water has reached the current," said Bertrand Chapron at the French Research Institute for Exploitation of the Sea. Chapron and colleague Fabrice Collard said they've combined surface roughness and current flow information with images from the ESA's Envisat satellite to monitor the proximity of the oil to the current.
"Now that oil has entered the Loop Current, it is likely to reach Florida within six days," Chapron said, warning that since the Loop Current is a very intense, deep ocean current, its turbulent waters will accelerate the mixing of the oil and water in the coming days.
"This might remove the oil film on the surface and prevent us from tracking it with satellites, but the pollution is likely to affect the coral reef marine ecosystem," Collard said.
The ESA said the Loop Current joins the Gulf Stream -- the Northern Hemisphere's most important ocean-current system -- sparking fears that oil could be carried up the U.S. East Coast.