I was amazed to find out that there are bacteria in the ocean floor that have metabolisms roughly 10,000 times slower than those living at the surface of the seabed. This extremely slow lifestyle may allow them to live very long lives. In fact, these microbes were found in a core sample of clay collected up to 20 meters beneath the seafloor of the North Pacific Gyre, just north of Hawaii. This depth means that the microbes settled on the ocean floor about 86 million years ago! While these as yet unidentified microbes rely on oxygen for survival, very little nutrients are available due to the large ocean currents in this area. Therefore, researchers have suggested they are still persisting off of food that arrived during the time of the dinosaurs.
National Public Radio
Roy H, Kallmeyer J, Adhikari RR, Pockalny R, Jorgensen BB, D’Hondt S. Aerobic Microbial Respiration in 86-Million-Year-Old Deep-Sea Red Clay. Science 18 May 2012:
Vol. 336 no. 6083 pp. 922-925.