Last month I wrote about the purported clean-up of the BP spill by oil-eating microbes gone on a feeding frenzy. This kind of clean-up by microbes has happened throughout time (such as when natural oil leaks occur on the ocean floor and the organisms kick into overdrive). In our more recent history, scientists have played with the idea of engineering microbes for purposes of this kind of "bioremediation."
NRDC has a recent article by Emily Voigt on the subject. She points out the problems in thinking that bioremediation will cure our ills without leaving some problems of its own in its wake:
"The microbial feeding frenzy that inevitably follows an oil spill upsets the equilibrium of the ocean: blooms of bacteria, for example, deplete oxygen levels. And should heavy hydrocarbons settle onto the cold seafloor, blanketing one of the most diverse ecosystems on earth, the resulting tar field would persist indefinitely, like some sort of deep-sea parking lot."
And as I noted before, and she mentions here again, these oil-eating microbes are naturally adapted to consume one specific substance, and if engineered, perhaps they may consume several chemical compounds at at time. But when crude oil spills into the ocean, it contains "tens of thousands of different hydrocarbons, from simple gases such as methane to complex liquids like benzene." Thats a tall order for such little guys.