The last two decades have seen a steep increase in scientific research focused on serpentinites. One of the key reasons for this growing interest has been the realization that molecular hydrogen (H2) and methane (CH4) produced during serpentinization can be utilized by many types of microorganisms to gain metabolic energy. By converting the energy into biomass, these organisms have the capacity to support entire biological communities based on chemical energy rather than photosynthesis. The prospect that these biological communities exist with little or no photosynthetic input suggests that they might be modern analogs of communities that existed on early Earth. It is also possible that such communities exist on other planetary bodies in our Solar System, such as Mars and Jupiter's moon Europa, whose surfaces appear too hostile to allow the presence of photosynthetic organisms. In recent years, these ideas have stimulated ongoing efforts by geomicrobiologists, astrobiologists, and others to characterize the microbial populations of serpentinites and to understand their relationship with the geochemical environment in which they live.
Here, we provide a brief overview of the geochemical context for serpentinite-hosted biological communities, and we summarize the results of recent investigations into the function and composition of those biological communities. We conclude with a discussion of the potential relationship between serpentinites and the origin and early development of life on Earth, and the possibility that serpentinite-hosted biological ecosystems might exist elsewhere in our Solar System.