Turning the muck at the bottom of the ocean into a valuable source of energy, is a lot less improbable than it might seem, thanks to microbiologist Daniel Bond. Three years ago U.S. Navy researchers discovered that a graphite rod dtuck in sea muck generates microwatts of electricity. This past year, Bond helped explain why. The senior research fellow at the University of Massachusetts showed that bacteria collect on the rod, feed on organic compounds in the muck, and transfer electrons to the graphite, creating current. Bond and colleagues have since turned that insight into a practical fuel cell. Bond places the bacteria inside a glass chamber and feeds then organic matter; in response, the bacteria create a usable current. The bacteria in the fuel cell can feed on contaminants such as toluene. Bond’s goal is to optimize the fuel cells to generate large amounts of electricity. If he succeeds, the bacteria-based fuel cells could transform sewage plants into power plants.