Are the Microbes Effective Enough?

"Microbes are available now but they are not effective for the most part," says marine microbiologist Jay Grimes of the University of Southern Mississippi. At this point, there are no man-made microbes that are more effective than naturally occurring ones at utilizing hydrocarbons.

The natural world is replete with a host of organisms that combine as a community to decompose oil—and no single microbe, no matter how genetically enhanced, has proved better than this natural defense. "Every ocean we look at, from the Antarctic to the Arctic, there are oil-degrading bacteria," says Atlas, who evaluated genetically engineered microbes and other cleanup ideas in the wake of the Exxon-Valdez oil spill in Alaska. "Petroleum has thousands of compounds. It's complex and the communities that feed on it are complex. A superbug fails because it competes with this community that is adapted to the environment."

Nor is it easy to help the existing communities of thousands of microbes, such as various species of Vibrio and Pseudomonads, to eat the oil faster—seeding experiments have generally failed. "Microbes are a lot like teenagers, they are hard to control," says marine chemist Chris Reddy of the Woods Hole Oceanographic Institution. "The concept that nature will eat it all up is not accurate, at least not on the time scale we're worried about."

Just like your automobile, these marine-dwelling bacteria and fungi use the hydrocarbons as fuel—and emit the greenhouse gas carbon dioxide (CO2) as a result. In essence, the microbes break down the ring structures of the hydrocarbons in seaborne oil using enzymes and oxygen in the seawater. The end result is ancient oil turned into modern-day bacterial biomass—populations can grow exponentially in days. "Down in the Gulf of Mexico there is an indigenous population [of microbes] adapted to oil from so much marine traffic and daily spills. Oil is not new," says Lee, who has also been monitoring the plumes of oil beneath the surface. "There are so many natural seeps around the world that if it wasn't for microbes we would have a lot of oil in the oceans."