Ecosystem Recovery from Deepwater Horizon Oil Spill Will Take Decades

It will likely take decades before the deep-sea ecosystem around the Deepwater Horizon oil spill site recovers from the impacts of the environmental disaster, according to new research published in the journal PLOS One.

When the well head blew out on the Deepwater Horizon oil rig in April 2010, nearly 5 million barrels (210 million gallons) of oil spewed from the ocean floor, encroaching upon the soft-sediment ecosystem in place at the bottom of the Gulf of Mexico. The oil spill and plume covered nearly 360 square miles -- about the size of Dallas, Texas. Within a range of nine square miles around the well head, scientists found the most severe reduction in biological abundance and biodiversity.

The research, presented by a multidisciplinary team from state and federal organizations, as well as representatives from BP, the operator of the oil rig, is reportedly the first to give comprehensive results of the oil spill's effect on deep-water communities at the base of the Gulf of Mexico's food chain.

The research team analyzed the soft-bottom, muddy habitats that make up the deep-sea ecosystem, looking specifically at biological composition and and chemicals at the same time at the same location.

"As the principal investigators, we were tasked with determining what impacts might have occurred to the sea floor from the Deepwater Horizon oil spill," said Paul Montagna of Texas A&M University-Corpus Christi, who specializes in Gulf of Mexico studies. "We developed an innovative approach to combine tried and true classical statistical techniques with state of the art mapping technologies to create a map of the footprint of the oil spill."

"Normally, when we investigate offshore drilling sites, we find pollution within 300 to 600 yards from the site," Montagna said. "This time it was nearly two miles from the wellhead, with identifiable impacts more than ten miles away. The effect on bottom of the vast underwater plume is something, which until now, no one was able to map. This study shows the devastating effect the spill had on the sea floor itself, and demonstrates the damage to important natural resources."

Jeff Baguley, a University of Nevada, Reno expert on meiofauna, small, waterborne invertebrates that range in size from 0.042 to 0.300 millimeters in size, said the that the oil spill dramatically reduced the once tremendous biodiversity of meiofauna in the deep sea regions of the Guld of Mexico.

"Nematode worms have become the dominant species at sites we sampled that were impacted by the oil. So though the overall number of meiofauna may not have changed much, it's that we've lost the incredible biodiversity," he said.