Chemolithotrophs: The Primary Producers of Acidic Geothermal Springs

Whether you are looking for life on other planets, or wondering what life may have been like in primitive environments on earth, acidic geothermal springs of Yellowstone National Park may provide important clues. The thermophilic organisms in these systems not only thrive at high temperatures, they contend with acidic waters and toxic elements such as ar senic, sulfide, mercury and boron. The Norris Geyser Basin in Yellowstone National Park contains many acidic (pH<3), arsenic-rich geothermal springs that do not support the growth of photosynthetic microorganisms. Conversely, these geothermal ecosystems are rich in chemical energy in the form of reduced species such as methane (CH4), hydrogen (H2), sulfide (H2S), arsenite (H3AsIIIO3) and ferrous iron (FeII). Thermal Biology Institute scientists McDermott and Inskeep are focused on the unique microbial populations inhabiting the extreme thermal environments that would be considered Superfund sites if they were not naturally occurring geothermal features of a National Park! Indeed, these extreme environments are thought to be possible analogs of primitive environments on earth and may prove to contain microorganisms with novel metabolisms that have yet to be discovered.

Their work is also the focus of an NSF-funded Microbial Observatory in Chemolithotrophyon acid-sulfate-chloride geothermal springs, where discovery is centered on the hypothesis that an understanding of microbial sequence diversity in nature will ultimately originate from a detailed description of the geochemical habitats and associated microbial physiologies that have defined the evolutionary history of adapted microbial populations. Inskeep and McDermott believe that a multidisciplinary approach in microbiology, microbial ecology and geochemistry is necessary to unravel the secrets of microbial life adapted to these extreme environments.