A report published in the journal Science asserts there’s a 35-kilometer long submerged plume of oil in the depths of the Gulf of Mexico. The oily cloud measured two kilometers wide and 200 meters thick, and was drifting through the Gulf at a depth of at least 900 meters. The report is the most authoritative challenge yet to White House assertions that most of the 5 million barrels of oil that leaked into the Gulf are gone. “These results indicate that efforts to book-keep where the oil went must now include this plume,” said Christopher Reddy, one of the members of the team from Woods Hole Oceanographic Institute. The report also said that the plume was slow to break down by natural forces, which means the oil could have traveled long distances in the Gulf before it was degraded.