Two studies shed more light on Gulf oil disaster
Two studies released this week highlight the size of the 2010 Gulf oil disaster and how nature played a key part in its cleanup.
Size of the disaster. Scientists with the National Oceanic and Atmospheric Administration reported this week that detailed chemical measurements showed 11,130 tons of oil and gas chemicals spilled in the disaster, which confirmed “the official average leak rate estimate of about 11,350 tons of gas and oil per day (equal to about 59,200 barrels of liquid oil per day). “ Learn more.
“This study uses the available chemical data to give a better understanding of what went where, and why,” said Thomas Ryerson, Ph.D., a NOAA research chemist and lead author of the study. “The surface and subsurface measurements and analysis provided by our university colleagues were key to this unprecedented approach to understanding an oil spill.”
Nature’s part. A new study funded by the National Science Foundation showed that underwater topography, ocean currents and bacteria in the Gulf of Mexico played key roles in causing methane and other chemicals from the spill to be cleaned up. Learn more.
“As scientists continue to peel apart the layers of the Deepwater Horizon microbial story,” said Don Rice, director of NSF’s chemical oceanography program, “we’re learning a great deal about how the ocean’s biogeochemical system interacts with petroleum–every day, everywhere, twenty-four/seven. “
According to a computer model developed by scientist David Valentine and others, the physical structure of the Gulf — kind of an underwater box canyon — was important to microbial scrubbing of millions of metric tons of spewed material. According to a news release:
“As a result, it’s not a river down there; it’s more of a bay. And the spill happened in a fairly enclosed area, particularly at the depths where hydrocarbons were dissolving.”
When the hydrocarbons were released from the well, bacteria bloomed. In other locations outside the gulf, those blooms would be swept away by prevailing ocean currents. But in the Gulf of Mexico, they swirled around as if they were in a washing machine, and often circled back over the leaking well, sometimes two or three times.
“What we see is that some of the water that already had been exposed to hydrocarbons at the well and had experienced bacterial blooms, then came back over the well,” Valentine said. “So these waters already had a bacterial community in them, then they got a second input of hydrocarbons.”
As the water came back over, he explained, the organisms that had already bloomed and eaten their preferred hydrocarbons immediately attacked and went after certain compounds. Then they were fed a new influx of hydrocarbons.
