Methane-munching microbes living in the deep biosphere for 400 million years: An analogue for extra-terrestrial life

It is becoming more and more appreciated that a major part of the biologic activity is not going on at the ground surface, but is hidden underneath the soil down to depths of several kilometres in an environment coined the “deep biosphere”. Studies of life-forms in this energy-poor system have implications for the origin of life on our planet and for how life may have evolved on other planets, where hostile conditions may have inhibited colonization of the surface environment. The knowledge about ancient life in this environment deep under our feet is extremely scarce.
Strange & Offbeat: Fossils & Ruins News — ScienceDaily