In 2010 , the Deepwater Horizon drilling rig spill up to 4.6 million barrelful of fogey petroleum into the Gulf of Mexico . But after all the fair up try , various government and BP gang still have n’t locate all 200 million congius . Now , some of that “ missing ” petroleum has finally turned up — or down , rather , buried in the deposit on the Gulf level . The oil cause particles in the open water to clump together and sink .

To find out where these might have settle , Jeffrey Chanton of Florida State Universityand colleagues used radioactive isotope carbon-14 as a tracer . Since fossil oil does n’t have carbon-14 , any sediment check petroleum would be blatant . They took 62 sediment core from an area comprehend 24,000 square kilometers ( 9,266 hearty mi )   around the spill website , Live Science reports , avoiding area with rude oil colour seeps . Then , using geographical information system ( GIS ) map , the team was able to chart the distribution of the oiled deposit .

According to their reckoning , some 6 million   to 10 million gallons are buried about a hundred kilometers south-east of the Mississippi Delta . This in all probability represents between 3 and 4.9 per centum of the petrocarbon that was released ( though some approximation put it at 9.1 pct ) . " This is the first time we ’ve ever really demonstrated that this is happening,”Chanton tells the Tallahassee Democrat . “ There was anecdotal data this was hap . This really quantifies it . "

sink to the bottom of the sea might have been good in the poor - term , since it clears the H2O . But in the tenacious outpouring , he explains , it ’s a trouble . Because there ’s less atomic number 8 on the ocean floor compared to the water pillar , the oiled particles are more likely to become hypoxic — or O deficient . That makes it harder for germ to help decompose the rock oil and it ’ll linger longer . “ This is going to affect the Gulf for years to arrive , ” Chanton says in anews release . “ Fish will likely ingest contaminants because worm ingest the deposit , and fish run through the insect . It ’s a conduit for contamination into the food entanglement . ”

Thefindingswere published in the American Chemical Society’sEnvironmental Science & Technologylast month .

Last yr , Chanton ’s squad shew thatmethane - derived carbon copy from the spill has already get in the food web . Methane - eating bacteria were very efficient in converting the natural gas into biomass , and their population bloomed when the fall occurred .