Deepwater Horizon Oil May Sit On Ocean Floor, But How Did It Get There?

Photo by U.S. Coast Guard via Getty Images

Ever since an explosion at BP’s Deepwater Horizon offshore rig in 2010 released about five million of barrels of oil into the Gulf of Mexico, researchers have been trying to figure out where much of the oil ended up. A new study is offering some answers.

By tracing chemicals in undersea sediment, scientists have found what appears to be a layer of oil on the ocean floor concentrated within 25 miles of the busted well. They believe up to sixteen percent of all the crude released during the spill may be found in that footprint.

“We found a really high amount of this tracer called hopane in the top one centimeter, which is where you would expect it to be, in the sediment. There’s a very sharp footprint right near the Deepwater Horizon well that certainly points towards that as the source,” says Burch Fisher. He was one of the scientists who worked on the project at UC Santa Barbara and is now a researcher at UT’s Jackson School of Geosciences.

He says it’s a striking discovery because oil often floats on the ocean surface after a spill.

“We kind of opened the door to sort of new research as to how the oil actually sunk in the first place,” he says. Fisher says it was “potentially microbes, potentially some of the dispersants that they sprayed that could be part of it.”

The research, published this week in the Proceedings of the National Academy of Sciences, bolsters other work that blamed the Deepwater Horizon spill for damage to coral in the Gulf.

The possibility that dispersants used to break up the oil could have contributed to the footprint on the floor of the Gulf may heighten calls for closer scrutiny of dispersants. Some environmental groups have already suggested that dispersants could have damaged the Gulf ecosystem.

While the study may have located some of the oil released by the Deepwater Horizon disaster, an estimated 70 percent of the oil still remains unaccounted for.