A remote controlled submarine is being used to study mysterious bacteria living a half a mile below the surface of Monterey Bay. The research is led by University of California, Davis, microbial ecologist Doug Nelson. The team uses a remote operated vehicle (ROV) owned and operated by the Monterey Bay Aquarium Research Institute (MBARI). The ROV Ventana is equipped with high-definition cameras and laser measuring equipment, and its arms can be fitted with a variety of collecting and sampling equipment. Because of their strange and hostile habitat, deep-sea bacteria have evolved survival strategies found nowhere else on Earth. Far from the sun, they live on hydrogen sulfide seeping from cracks in the seafloor, and use nitrate in seawater instead of oxygen. One example is Thiomargarita namibiensis, a giant bacteria that grows to almost a millimeter in size -- 100 times the size of any other known bacterium. Thiomargarita was discovered in 1999 in deep water off the coast of Namibia in southern Africa, by a team led by German scientist Heide Schulz. This year, Schulz will join the UC Davis researchers studying bacteria around sulfide seeps in Monterey Canyon. Nelson's lab is particularly interested in Beggiatoa, bacteria that grow in long filaments on the sea-floor mud. Although these bacteria are deep in the ocean, they can be affected by fertilizer runoff, aquaculture and dumping of waste at sea, said Nelson. "If you insult the ocean in a significant way, it will result in a die-off," said Nelson. That could lead to a release of hydrogen sulfide from the seafloor, which could affect fish and other marine animals and plants. Website: .