Oil from BP spill may be sitting on seafloor

Oil that gushed from the 2010 Deepwater Horizon site may be lying low.

As much as 16 percent of the approximately 5 million barrels of oil let loose into the Gulf of Mexico may have settled into the seafloor, within a 40-kilometer radius of the damaged oil well. That sunken oil may account for up to about 30 percent of the approximately 2 million barrels of oil that scientists suspect never reached the ocean’s surface. Researchers want to track down all of the lost oil to assess the full extent of the ecological damage.   

Led by David Valentine of the University of California, Santa Barbara, the researchers found the submerged oil by searching for hopane. The hardy hydrocarbon acts as a calling card for oil in the environment because it’s one component of oil that is not easily broken down. By analyzing more than 3,000 ocean sediment samples from 534 locations in the gulf, the researchers mapped patches of the remaining oil, sunken in a 3,200-square-kilometer region around the well, an area slightly smaller than Long Island.

The finding, reported October 27 in the Proceedings of the National Academy of Sciences, suggests that the rest of the unseen oil may still be hiding elsewhere in the ocean.