Oil from the BP spill remains stuck on the bottom of the Gulf of Mexico and is not degrading as had been hoped, according to a top scientist.
Marine scientist Samantha Joye's report is at odds with a recent report by the BP spill compensation czar that said nearly all will be well by 2012.
Ms Joye, of the University of Georgia, told a science conference in Washington that she went to places she had visited in the summer and that the oil and residue from oil-munching microbes had not cleared up, as had been expected.
She told the American Association for the Advancement of Science annual conference: "There's some sort of a bottleneck we have yet to identify for why this stuff doesn't seem to be degrading.
"Magic microbes consumed maybe 10% of the total discharge, the rest of it we don't know. There's a lot of it out there."
A Department of Energy scientist, doing research with a grant from BP from before the spill, said his examination of oil plumes in the water column show that microbes have done a "fairly fast" job of eating the oil. Lawrence Berkeley National Lab scientist Terry Hazen said his research differs from that of Ms Joye because they looked at different places at different times.
Ms Joye also said her research shows that the burning of oil left soot on the sea floor, which still had petroleum products. Even more troublesome was the amount of methane from the BP well that mixed into the Gulf and was mostly ignored by other researchers
Earlier this month, Kenneth Feinberg, the government's oil compensation fund czar, said based on research he commissioned, the Gulf of Mexico would almost fully recover by 2012 - a statement Ms Joye disagrees with.
She said: "I've been to the bottom. I've seen what it looks like with my own eyes. It's not going to be fine by 2012. You see what the bottom looks like, you have a different opinion."