A Florida State University oceanography professor is questioning government estimates that the vast majority of the oil from the Deepwater Horizon spill is already gone from the Gulf or is being rapidly broken down by bacteria.

“I think the imprint of the BP release, the discharge, will be detectable in the Gulf of Mexico for the rest of my life,’ Ian MacDonald told a congressional hearing on the spill. He was quoted in an Aug. 20 Wall Street Journal article that also referred to the findings of other scientists who had observed a vast underwater plume of hydrocarbons the size of Manhattan near the site of the Deepwater Horizon disaster.