Scientists probe the life in rocks San Francisco Chronicle

Armed with the modern tools of biotechnology, scientists are unraveling secrets of the most ancient life forms on Earth — methane-eating microbes that inhabit deep sediments on the ocean floor, or sulfur-breathing bacteria that lurk in dark fissures miles below ground. To the researchers in the arcane but fascinating field of “geobiology,” the distinction between the study of life and the study of Earth is blurred. The minerals beneath us so teem with life that these scientists speak of rocks being “alive.”