Studies over the past decade have revealed that life may have penetrated every possible niche where there is an exploitable source of energy. Moreover, life is a major geochemical force which apparently has effects over a wider range of environments than previously appreciated. Extreme environments such as those at high temperature hydrothermal vents offer a good example to the extent to which geochemistry can control or influence the distribution and physiology of microorganisms, and the extent to which the organisms can transform their geochemical environment. An integrated interdisciplinary approach is proposed using a combination of molecular ecological tools, biogeochemical measurements and standard microbiological methods to determine the community and geochemical dynamics in these ecosystems. Specifically, the objective of the study is to establish how deeply branching lineage of the Archea and Bacteria in high temperature ecosystems transform their geochemical environments. Field work will be conducted in Yellowstone National Park. Detailed geochemical and biological analyses along the temperature gradients will provide the framework for addressing specific questions regarding the growth and physiology of the members of the communities. The results of this study will provide a much needed baseline of ecological and geochemical data, and offer quantitative models of the geochemical bioenergetics associated with these high temperature ecosystems. With the elucidation of the key biogeochemical parameters it should be possible to predict the factors that determine the distribution, dynamics, and growth requirements of the deepest lineages within the Archea and Bacteria. Furthermore, this study will challenge our perspective of biogeochemical and microbiological processes, theories on the origins of life and provide predictions about life forms that may exist on other planets.
