Geochemical Attributes and Gradients Within Geothermal Systems Define the Distribution of Specific Microbial Populations
Abstract
Microorganisms in natural habitats interact with mineral surfaces in many different respects. For example, microorganisms are known to enhance the dissolution rates of some minerals via the production of organic acids and other exudates, but at the same time, may mineralize solid phases as a direct or indirect result of metabolic processes. It is also well-established that many microorganisms form biofilms on mineral surfaces, and may preferentially attach to surfaces rich in necessary nutrients or in elements used for energy conservation. In part due to the complexity of natural soil, water and sediments systems, it is generally difficult to ascertain mechanisms controlling the distribution of organisms on mineral surfaces and their role in mineral precipitation-dissolution reactions. Geothermal microbial communities are often less diverse than surface soils and sediments and offer opportunities for understanding relationships among specific microbial populations and geochemical processes that define the biogeochemical cycles of individual elements. We have investigated numerous acidic and near-neutral geothermal sites in Yellowstone National Park, and have performed a number of complimentary chemical and microbiological analyses to ascertain the role of microorganisms in S, Fe, As and Sb cycling in geothermal systems. Our results demonstrate the importance of microbiota in the formation of various Fe(III) oxide phases with variable anion chemistry, and the importance of chemolithotrophic metabolisms in Fe, S and As cycling. Where possible, these metabolisms are linked to specific microbial populations identified via molecular methods, and in some cases confirmed using isolation and characterization of individual organisms.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFM.B14B..01I
- Keywords:
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- 0419 Biomineralization;
- 0448 Geomicrobiology;
- 0463 Microbe/mineral interactions;
- 0471 Oxidation/reduction reactions (4851);
- 0488 Sulfur cycling