A significant portion of the remaining oil from the 2010 Deepwater Horizon oil spill is sitting on the bottom of the Gulf of Mexico, within 25 miles (40 kilometers) of the well, a new study finds.
The BP-operated Macondo well exploded in April 2010, and gushed an estimated 5 million barrels of oil into the ocean before engineers finally capped the well in July 2010. Since that time, research has suggested that the spilled oil has affected wildlife ranging from dolphins to corals. In 2014, researchers at Pennsylvania State University reported that coral communities up to 13.7 miles (22 km) from the spill site showed damage.
Now, researchers have tracked the path of oil from the water column to the ocean floor, and they found the final resting place of between 2 and 16 percent of the total oil spilled.
"This analysis provides us with, for the first time, some closure on the question, 'Where did the oil go, and how did it get there?'" Don Rice, the program director of the National Science Foundation's Division of Ocean Sciences, said in a statement. The NSF funded the research.
Tracing a spill Scientists estimate that about 2 million barrels of Deepwater Horizon oil ended up in the deep ocean. Tracing that oil has been challenging. [SOS! 10 Major Oil Disasters at Sea]
A research team led by David Valentine, a microbial geochemist at the University of California, Santa Barbara, sampled more than 534 locations near the spill site, gathering more than 3,000 individual samples. They analyzed the samples for a hydrocarbon called hopane, which is found in oil and persists in the environment for a long time.
The researchers found an area of 1,250 square miles (3,237 square km), mostly southwest of the Macondo well, where a thin sheen of oil rests in patches on the top half-inch of the seafloor, according to the NSF.