Scientists discover ‘blizzard' silting oil on bottom of Gulf

Kate Spinner - 

A mixture of oil and dead organic particles may still be falling to the deep bottom of the northern Gulf of Mexico, potentially harming the base of a food web that supports all kinds of sea life, from giant whales and blue-fin tuna to grouper and snapper.

In water thousands of feet deep, scientists have discovered a "dirty blizzard" that deposited more than three inches oil mixed with decayed plant and animal material near the site of the BP Deepwater Horizon blowout last year.

A quarter to half of the oil that spewed from the blown wellhead - between 186 million to 227 million gallons - is still unaccounted for and thought to be lingering in the deep sea, said Benjamin Flower, a geological oceanographer with the University of South Florida.

"The key is that it is not out-of-sight, out-of-mind. It's a case where it can affect the base of the food chain," Flower said.

Flower's research team took core samples from sediments 1,300 to 3,600 feet deep. Each core was nearly 20 inches thick, representing about 1,000 years of accumulation.

More than three inches accumulated in a period of three months, more than three times the rate of normal sedimentation.

"This is a unique sedimentation event. It hasn't happened before in this area," Flower said.

Scientists concluded the debris accumulated in the months after the spill by examining stable elements within the material. Additionally, the cores — the last was taken in February — captured a small amount of seawater to make sure that the top layer of sediment did not get disturbed.

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