Biogeography of serpentinite-hosted microbial ecosystems
Abstract
Ultramafic rocks in the Earth's mantle represent a tremendous reservoir of carbon and reducing power. Upon tectonic uplift and exposure to fluid flow, serpentinization of these materials generates copious energy, sustains abiogenic synthesis of organic molecules, and releases hydrogen gas (H2). To date, however, the "serpentinite microbiome" is poorly constrained- almost nothing is known about the microbial diversity endemic to rocks actively undergoing serpentinization. Through the Census of Deep Life, we have obtained 16S rRNA gene pyrotag sequences from fluids and rocks from serpentinizing ophiolites in California, Canada, and Italy. The samples include high pH serpentinite springs, presumably representative of deeper environments within the ophiolite complex, wells which directly access subsurface aquifers, and rocks obtained from drill cores into serpentinites. These data represent a unique opportunity to examine biogeographic patterns among a restricted set of microbial taxa that are adapted to similar environmental conditions and are inhabiting sites with related geological histories. In general, our results point to potentially H2-utilizing Betaproteobacteria thriving in shallow, oxic-anoxic transition zones and anaerobic Clostridia thriving in anoxic, deep subsurface habitats. These general taxonomic and biogeochemical trends were also observed in seafloor Lost City hydrothermal chimneys, indicating that we are beginning to identify a core serpentinite microbial community that spans marine and continental settings.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.B41F..07B
- Keywords:
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- 0450 BIOGEOSCIENCES / Hydrothermal systems;
- 0456 BIOGEOSCIENCES / Life in extreme environments;
- 0463 BIOGEOSCIENCES / Microbe/mineral interactions;
- 0465 BIOGEOSCIENCES / Microbiology: ecology;
- physiology and genomics