One year after the Deepwater Horizon blow-out began the worst oil spill in US history, scientists continue to investigate the effects of the oil and its residues.
Samantha Joye/University of Georgia/AP/File
A year after the worst off-shore oil spill in US history began, scientists continue to sample the sea floor and comb beaches and marshes in an attempt to track the fate of oil that spewed for nearly three months from the Deepwater Horizon blow-out.
But the emphasis has long since shifted from debates over a simple "Where's Waldo" kind of accounting, to measuring how the oil degrades with time in various environments, and the effects the remnant chemicals can have on the habitats they encounter.
The effort should give restoration teams a better sense of where they need to focus their work. It should also provide benchmarks to more effectively gauge the resilience of land and ocean organisms after their assault by oil and the dispersants used to break up slicks.
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The BP spill "gave nature a stress test," says marine scientist Christopher Reddy of the blow-out's environmental aftermath. In trying to assess how nature is responding, it's vital to know how the chemical agents responsible for the stress change over time, he says.
Shortly after BP capped the blow-out on July 14, and oil stopped flowing, federal officials released a checkbook-like accounting of the oil's fate. But it proved controversial.
The uncertainties in some of the categories were large. The report had not undergone a rigorous peer review. Indeed, the numbers were never meant to represent a rigorous, definitive accounting, according to a white paper prepared by the staff of the National Commission on the BP Deepwater Horizon Spill and Offshore Drilling.