New study finds Gulf spill harmed life on sea floor

Tiny organisms living on the soft, sandy floor of the Gulf of Mexico near BP’s ill-fated Macondo well will need decades to recover from harm caused by the 2010 oil spill, a new report concludes.

The study, published this week in the scientific journal PLoS One, found most damage to life on the sea floor within 11 square miles around the wellhead, with at least some injury to bottom-dwelling animals for about 57 square miles.

Researchers said the study represents the first attempt to show the spill’s impact on the deep-water communities at the base of the Gulf’s food chain. The study, funded in part by BP, will be used by the federal government to determine the ecological toll of the spill and how much the London-based company should pay to mitigate the damage.

“Early on there was a widespread expectation that there would be no effects in the deep sea, that the oil would float,” said Paul Montagna, one of the study’s authors and a marine biologist at the Harte Research Institute for Gulf of Mexico Studies in Corpus Christi. “What we found were effects for many miles.”

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The research team, which included scientists from the University of Nevada and the National Oceanic and Atmospheric Administration, looked at sediment samples taken during two surveys in fall 2010 after 193 million gallons of oil had flowed from the well.

The analysis found a correlation between the abundance and diversity of crustaceans and tiny worms in the mud and hydrocarbons and heavy metals linked to the well. The scientists did not see a similar tie between marine life and natural seeps of oil.

Cynthia Cooksey, a scientist with the National Oceanic and Atmospheric Administration, said researchers currently are analyzing data collected from sites sampled in spring 2011. “This is not yet a complete picture,” she said.

BP questioned the initial findings, saying the researchers provided no data to support the claim that it could take decades for the species in the study to recover.

“In fact, the researchers acknowledge that little is known about recovery rates of these communities following an event such as this,” said Jason Ryan, a BP spokesman in Houston. The study “confirms that potential injury to the deep sea soft sediment ecosystem was limited to a small area in the immediate vicinity of the Macondo well-head” first identified in 2010.

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Montagna, the study’s co-author, said he expects it will take a long time for the ecosystem to recover because the deep sea is as cold as a refrigerator. “It’s certainly reasonable to assume that the oil won’t degrade for awhile,” he said.

The research team hopes to take more samples this year and plans to follow the sea floor’s recovery over time, Montagna said.

The analysis is part of the Natural Resources Damage Assessment, which is the government’s primary tool to hold BP accountable for the spill. Federal law requires the offshore well’s primary leaseholder, BP, to cover the cleanup costs and a portion of the damage, but the company can challenge the scientific findings in court.