G o a l s
Linking Phylogeny and Biogeochemistry for the Discovery of Novel Chemolithotrophs Inhabiting Geothermal
Gradients in Yellowstone National Park

Norris Geyser Basin in Yellowstone National Park represents one of the most diverse geochemical environments on Earth, and the perfect venue for a comprehensive research thrust aimed at discovering novel chemolithotrophic microorganisms. In terms of described general physiological groups, chemolithotrophs are tremendously underrepresented - particularly given the predominance of inorganic energy sources in our biosphere. Our microbial observatory is located in Hundred Springs Plain, Norris Geyser Basin, a dynamic geothermal complex comprised of hundreds of thermal acid-sulfate-chloride springs that vary significantly with respect to inorganic constituents and temperature – both are significant environmental selectors that occur in numerous gradients in these springs.

These springs contain high concentrations of Fe2+, S0, H2, H2S, and As(III) which represent the predominant potential electron donors driving nonphotosynthetic primary production. Our research utilizes novel cultivation and molecular techniques to describe, characterize, and isolate the microbial populations present along geochemical and temperature gradients. This detailed description of the microbiology is accompanied by a complete analysis of the aqueous and solid phase geochemistry associated with these communities and that no doubt select for, and define, the populations inhabiting these inorganic environments.

Our specific objectives are:

Objective 1: Characterize aqueous and surface chemical processes associated with S, Fe and As cycling in acid-sulfate-chloride thermal springs, emphasizing the nature of chemical gradients and microenvironmental conditions that define the ecological context of native microbial populations.

Objective 2: Employ culture-independent techniques, including a novel PCR approach, to describe native microbial populations, examine community dynamics, and to correlate community composition with the geochemical perspectives derived from Objective 1.

Objective 3: Apply more realistic cultivation approaches that account for key environmental factors and that utilize surfaces and flow-through systems to isolate previously uncultured microorganisms or whole communities involved in chemolithotrophic metabolism.

In addition to offering significant promise for discovery of previously unknown microorganisms, our studies contribute significantly to the general development of microbial ecology principles. Our comprehensive, multidisciplinary approach links molecular description with the more difficult task of understanding the relevance of specific microbial populations in their natural environments and the patterns in microbial ecology that reflect the environmental context of specific phylogeny.

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