Integration of Metagenomic and Stable Carbon Isotope Evidence Reveals the Extent and Mechanisms of Carbon Dioxide Fixation in High-Temperature Microbial Communities.

Although the biological fixation of CO by chemolithoautotrophs provides a diverse suite of organic compounds utilized by chemoorganoheterotrophs as a carbon and energy source, the relative amounts of autotrophic C in chemotrophic microbial communities are not well-established. The extent and mechanisms of CO fixation were evaluated across a comprehensive set of high-temperature, chemotrophic microbial communities in Yellowstone National Park by combining metagenomic and stable C isotope analyses. Fifteen geothermal sites representing three distinct habitat types (iron-oxide mats, anoxic sulfur sediments, and filamentous "streamer" communities) were investigated.