Where did the missing Deepwater Horizon oil go? It fell like dark rain onto the ocean floor
Tuesday, October 28, 2014, 6:44 PM - According to new research, millions of gallons worth of the oil that mysteriously 'vanished' after the 2010 Deepwater Horizon oil spill has been located on the ocean floor, and these findings may help to find the rest of it, and to fully assess the amount of damage caused by this disaster.
When the Deepwater Horizon offshore oil rig caught fire and exploded in April of 2010, it resulted in an estimated 4.7 million barrels of oil spilling into the waters of the Gulf of Mexico. It's been named the largest marine oil spill in the history of the petroleum industry.
Of that nearly 5 million barrels, around 2 million (totaling roughly 84 million gallons) were still unaccounted for, even now, over 4 years after the disaster. Some may have been consumed by plankton and other ocean organisms, but a large portion seemed to vanish without a trace.
However, a team of researchers plumbing the depths of the Gulf of Mexico report that they've located a up to 30 per cent of this lost oil, trapped in shallow deposits along an over 3,200-square-kilometre patch of the ocean floor.
How did all this oil, which was originally suspended under the water's surface, end up there? It rained down.
"Based on the evidence, our findings suggest that these deposits are from Macondo oil that was first suspended in the deep ocean, then settled to the sea floor without ever reaching the ocean surface," said lead researcher David Valentine, a biogeochemist at the University of California Santa Barbara, according to a press release from the National Science Foundation. "The pattern is like a shadow of the tiny oil droplets that were initially trapped at ocean depths around 3,500 feet and pushed around by the deep currents. Some combination of chemistry, biology and physics ultimately caused those droplets to rain down another 1,000 feet to rest on the sea floor."
Also, this new study is also lending support to previous research that found the Deepwater oil spill damaged corals in the region - research that had come under attack for its conclusions.
"The evidence is becoming clear that oily particles were raining down around these deep sea corals, which provides a compelling explanation for the injury they suffered," Valentine said in the press release. "The pattern of contamination we observe is fully consistent with the Deepwater Horizon event but not with natural seeps - the suggested alternative."
Hydrocarbons from the Deepwater Horizon spill overlaid on sea floor bathymetry of the study area. Credit: David Valentine et al.
According to the Associated Press, BP officials are disputing the researcher's claims. Jason Ryan, a spokesman for the company, wrote an email to Seth Borenstein, saying "the authors failed to identify the source of the oil, leading them to grossly overstate the amount of residual Macondo oil on the sea floor and the geographic area in which it is found."
However, as Borenstein reported:
"It's impossible at this point to do such chemical analysis, said Valentine and study co-author Christopher Reddy, a marine chemist at Woods Hole Oceanographic Institute, but all other evidence, including the depth of the oil, the way it laid out, the distance from the well, directly point to the BP rig."