National Geographic News 
Aug 21, 2010
A giant plume from BP’s Gulf of Mexico oil spill has been confirmed deep in the ocean—and there are signs that it may stick around, a new study says.
Many scientists had predicted that oil-eating bacteria—already common in the Gulf due to natural oil seeps—would process much of the crude leaked from BP’s Deepwater Horizon wellhead, which was capped July 15. (Read more about how nature is fighting the oil spill.)
But new evidence shows that a 22-mile-long (35-kilometer-long), 650-foot-high (200-meter-high) pocket of oil has persisted for months at depths of 3,600 feet (1,100 meters), according to a team from Woods Hole Oceanographic Institution (WHOI) in Massachusetts.
(Related: “Much Gulf Oil Remains, Deeply Hidden and Under Beaches.” )
The oil plume’s stability is “a little unexpected,” study leader Richard Camilli, of WHOI’s Applied Ocean Physics and Engineering Department, said at a Thursday press briefing in Washington, D.C.