Impacts to the deep  sea, soft-sediment ecosystem in a large area surrounding the 2010 Deepwater Horizon well head blowout and subsequent oil spill in the Gulf of Mexico were discovered.

Because the deep sea is cold, it could take decades to recover from the spill’s impacts, according to a scientific paper reported in the online scientific journal PLoS One.

“While a lot of focus was put on the surface effects of the oil spill, we were surprised to find that much of the oil never left the deep sea,” said Dr. Paul Montagna, Endowed Chair for Ecosystems and Modeling at the Harte Research Institute for Gulf of Mexico Studies, Texas A&M University -Corpus Christi. “The unseen effects are so much larger than the seen effects.”

The paper is the first to give comprehensive results of the spill’s effect on deep water communities at the base of the Gulf’s food chain, in its soft -bottom muddy habitats; specifically looking at biological composition and chemicals at the same time at the same location.

“This is not yet a complete picture,” said Cynthia Cooksey, NOAA’s National Centers for Coastal Ocean Science lead scientist for the spring 2011 cruise to collect additional data from the sites

sampled in fall 2010. “We are now in the process of analyzing data collected from a subsequent

cruise in the spring of 2011. Those data will not be available for another year, but will also

inform how we look at conditions over time.”

“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 Montagna. “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.” Click here for photos

“Normally, when we investigate offshore drilling sites, we find pollution within 300 to 600 yards from the site,” said Montagna. “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.”

The oil spill and plume covered almost 360 square miles with the most severe reduction of biological abundance and biodiversity impacting an area about 9 square miles around the wellhead, and moderate effects seen 57 square miles around the wellhead.

“The area we are talking about is about the same temperature as your refrigerator, 39 degrees. It is dark with a slow metabolic rate. Given these deep-sea conditions, it is possible that recovery in the vicinity of the Deepwater Horizon blowout will take decades or longer,” said Montagna.