Drs. Gary M. King of the University of Maine and Klaus Nusslein of the University of Massachusetts-Amherst have been awarded a grant from the NSF Life in Extreme Environment (LExEn) program to determine the role of atmospheric trace gases in microbial colonization and succession on recent lava flows. Volcanic activity has played an important role in the development of terrestrial ecosystems for much of Earth\u27s history, and continues to shape terrestrial environments at present. Deposition of lava and tephra result in surfaces that over time support complex, highly productive biological communities. However, young or recently extruded lavas represent extreme environments that contain few of the major nutrients necessary for sustaining life. Neither organic matter nor a fixed form of nitrogen (e.g., ammonium or nitrate) are readily available within or on the matrix of young lava. Thus, early colonization of lava by microbes requires a source of exogenous nutrients. Recent observations of young Hawaiian lava indicate that the atmosphere provides a significant source of carbon and energy for early microbial colonization. In particular, trace gases such as hydrogen and carbon monoxide (and possibly methane) serve as substrates that fuel the metabolism of functionally diverse microbes. Among these microbes are bacteria that use atmospheric nitrogen as a source of cellular nitrogen, and species that form important symbioses with plants. The nature of trace gas utilization by microbes colonizing young lavas will be the primary focus of this LExEn research effort. A variety of field and laboratory studies in the vicinity of the Kilauea volcano will document relationships among lava age (emphasizing chronosequences from 0-300 yr), microbial biomass, trace gas utilization (hydrogen, carbon monoxide and methane) and precipitation regimes (e.g., moist versus dry). Extractions of genomic DNA from lava will be used to determine the diversity of microbial communities across age and climate gradients, and the diversity of specific functional groups within these communities. Finally, the research will include efforts to enrich, isolate and characterize novel trace-gas utilizing microbes from young lava and to determine the significance of such isolates in situ. The research is expected to yield new insights about the survival and dynamics of microbes in extreme environments relevant for understanding both contemporary and ancient terrestrial systems as well as systems that might exist on other planets
