What happens to an ocean after a massive oil spill? Media attention may have drifted away from the Gulf of Mexico, but scientists are still there, studying the long-term impacts of last year’s BP Deepwater Horizon disaster.
One of those scientists is Samantha Joye. I’ve interviewed her before, for a story on BoingBoing about the tiny worms that live on underwater deposits of frozen methane. In her presentation at AAAS 2011, Joye focused on what she calls “microbial spit”—a slimy, organic substance produced when naturally occurring ocean bacteria dine on spilled oil. Joye thinks the spit is the mechanism responsible for carrying oil from the spill to the ocean floor, where it sits today.
Joye shared underwater images depicting eerie strings of bacterial slime — mucus streamers that ranged from one millimeter to almost two meters long. The key ingredient of the slime is what she terms bacterial spit, a material that, like laundry detergent, helps break apart large oil globules. Such surfactants are secreted by many oil-eating bacteria and render the oil easier for them to digest. As the sticky slime picks up cells and other debris from the water, it becomes heavy and sinks.
Or that’s what appeared to be happening, Joye said. To investigate, her team went back to the lab and added a milliliter of oil from the BP well to a liter of surface seawater that her group had collected from an oil-free part of the Gulf.
After just one day, naturally occurring microbes in the water began growing on the oil. After a week, the cells formed blobs, held together by spit, that were so heavy they began sinking to the bottom of a jar. Two weeks later, large streamers of microbial slime and cells were evident. Brown dots visible inside the mix were emulsified oil.
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Image: V. Asper/ Univ. of So. Miss.