Environment: Deepwater Horizon disaster may have caused a ‘dirty blizzard’ in the Gulf of Mexico

A NASA satellite image shows the widespread sheen of oil spreading across the Gulf of Mexico after the April 2010 failure of the Deepwater Horizon drilling operation.

Researchers try to trace fate of BP oil in the Gulf of Mexico

By Summit Voice

FRISCO—It’s been nearly three years since BP’s failed Deepwater Horizon drilling operation spewed millions of gallons of crude oil into the Gulf of Mexico, but scientists are still looking for signs of long-term impacts and trying to understand how the oil affected Gulf ecosystems.

One of the biggest questions remaining is exactly what happened to all the oil — about 5 million barrels. Along with a tiny percentage that was physically cleaned up, most studies suggest that much of the oil was processed by bacteria, or simply broken down into constituent molecules, but none of the studies have been able to account for the entire amount.

But during a recent New Orleans conference, Florida State University researchers presented a new hypothesis, saying that some of the oil acted as a catalyst for plankton and other surface materials to clump together and fall to the sea floor in a massive sedimentation event they describe as a “dirty blizzard.”

“Some of the missing oil may have mixed with deep ocean sediments, creating a dirty bathtub effect,” said FSU oceanography professor Jeff Chanton. “The sediments then fell to the ocean floor at a rate 10 times the normal deposition rates. It was, in essence, an underwater blizzard, said Chanton, of the FSU Earth, Ocean and Atmospheric Sciences department.

The oily sediments deposited on the sea floor could cause significant damage to ecosystems and may affect commercial fisheries in the future, he said.

The research conducted by the Deep-C Consortium used thorium, lead and radiocarbon isotopes in addition to DNA to analyze sediments and trace remnant oil.

The dirty blizzard hypothesis explains why layers of water that would normally be cloudy with suspended plankton instead appeared transparent during the spill, except for strings of particles falling to the bottom.

“The oil just sucked everything out of the surface,” Chanton said.

Chanton and his Deep-C colleagues are continuing their research to determine exactly how much of the oil ended up on the sea floor.

The Deep-C (Deep Sea to Coast Connectivity in the Eastern Gulf of Mexico) Consortium is composed of 10 major institutions involved in a long-term, interdisciplinary study of deep sea to coast connectivity in the northeastern Gulf of Mexico. The study is investigating the environmental consequences of the 2010 oil spill on living marine resources and ecosystem health.

The research was made possible in part by the Gulf of Mexico Research Initiative.

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