After Hurricane Isaac lashed the coasts of Mississippi and Louisiana, a fair amount of old, weathered oil and tar balls washed ashore.
Whence the oil?
Researchers from the University of Miami have collected samples and are looking to see whether they chemically match the petroleum from BP's Deepwater Horizon oil spill in the summer of 2010. The researchers also have taken measurements of underwater currents in the Gulf of Mexico before, during and after the storm to see how much upwelling Isaac caused.
While Isaac was moving through the gulf in late August, the researchers dropped probes from a National Oceanographic and Atmospheric Administration aircraft to measure conditions both in the air and in the water. After hitting the surface, the probes returned information about underwater currents in the DeSoto Canyon area, where the Deepwater Horizon spill occurred.
Hurricanes are capable of causing upwelling from deep underwater. But how much of the BP oil remained on the ocean bottom after the spill remains unclear.
"We wanted to collect data from the DeSoto Canyon area where the Deepwater Horizon incident occurred, so we could capture the upwelling as it was occurring," said co-principal investigator of the mission, Nick Shay, in a statement.
According to CBS News, laboratory tests show that globs of oil found on two Louisiana beaches after Hurricane Isaac came from the BP spill. Earlier this month, BP acknowledged that oil from its spill had been exposed by Isaac's waves and that the company would work to clean it up.