Microbial survival in strongly lithifying hotspring environments, Yellowstone National Park
Abstract
A new hotspring near the Narrow Gauge thermal feature in Yellowstone National Park is ~10 month old, rapidly-precipitates carbonate and hosts a diversity of microbial communities across a range of temperature and pH. The organisms that began to colonize different sites along the apron facies must avoid lithification for survival, and it is hypothesized that they achieve this by employing acid producing metabolic reactions. Oxidation of sulfur, for example, will yield protons, locally delaying CaCO3 precipitation by decreasing the acid neutralizing capacity of the water (ANC = [HCO3-] + 2[CO32-] + [OH-] - [H+]). Genomic and geochemical approaches were utilized to explore the microbial communities and some metabolic processes. Samples were collected for 16S rRNA gene sequencing, microscopy, membrane lipids analyses and both aqueous and rock geochemistry. Temperature and pH were determined in the field. The water chemistry indicates a source similar to other Mammoth Hot Springs and ∂13C analyses of aqueous and solid phases indicate localized changes due to CO2 fixation and respiration, as well as CO2 degassing from the source vent. Limited genomic diversity and differences in the membrane fatty acid patterns indicate highly selective conditions for communities with CO2 fixing and S-oxidizing metabolisms. Genes for key enzymes involved in these processes have been identified. Fatty acid composition corresponds with genomic data, indicating a difference in community structure between sites. CO2 fixation at two sites increases ANC, but S-oxidation and respiration decrease ANC, preventing the lithification of these communities. These analyses collectively indicate that microorganisms are able to stave off lithification long enough to form healthy microbial communities which then affect the rate of carbonate precipitation and likely affect facies development.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.B51I0510W
- Keywords:
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- 0419 BIOGEOSCIENCES / Biomineralization;
- 0448 BIOGEOSCIENCES / Geomicrobiology;
- 0463 BIOGEOSCIENCES / Microbe/mineral interactions