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Images: Oil, Microbes, and the Risk of Dead Zones

WHOI chemist Ben Van Mooy holds a sample of water taken from the plume of hydrocarbons more than 1,000 meters below the surface of the Gulf of Mexico. He has prepared the sample for the Winkler titration, a method that determines the concentration of oxygen dissolved in the water. Van Mooy's work in the Gulf showed that oxygen levels in and around the plume were not significantly lowered by microbial activity. (Photo by Dana Yoerger, Woods Hole Oceanographic Institution)

WHOI chemist Ben Van Mooy adds chemical reagents to water samples in preparation for an oxygen assay called the Winkler titration. The samples were taken from within and outside of the plume of oil from the ruptured wellhead at the Deepwater Horizon oil rig in the Gulf of Mexico. The Winkler method was developed in 1888 and is still the "gold standard" for determining oxygen concentrations in liquid samples. (Photo by Dana Yoerger, Woods Hole Oceanographic Institution)

A new technique for determing the concentration of oxygen in a liquid sample uses a laser (coming from the green fiber, right) and an oxygen-sensitive sticker called an optode (pale spot) inside the sample bottle. When struck by the laser, the sticker fluoresces; the wavelength of the light it gives off indicates the concentration of oxygen in the fluid around it. WHOI chemist Ben Van Mooy used this method to monitor microbial activity in samples of water taken from within and outside the oil slick on the surface of the Gulf of Mexico after the Deepwater Horizon oil spill. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)

From the deck of the research vessel Endeavor,Ben Van Mooy (right) and others survey the scene near the burning Deepwater Horizon oil rig in the Gulf of Mexico in June, 2010. Van Mooy was a member of a team of WHOI scientists who went to the Gulf to study aspects of the oil spill, including how fast it was flowing out of the ruptured wellhead and whether it was flowing in a deep plume of hydrocarbons. Van Mooy's experiments focused on whether microbes were eating oil in the surface slick and in the deep plume, and whether their activities were lowering oxygen levels enough to endanger fish and other marine life. (Photo by Dan Torres, Woods Hole Oceanographic Institution)