LExEn: Sulfuric Acid Speleogenesis by Chemolithotrophic Bacteria: Community Structure and Habitat Modification by Acid Extremophiles

University Of Texas At Austin, Austin TX

Investigators

Abstract

AWARD ABSTRACT Sulfuric Acid Speleogenesis by Chemolithotrophic Bacteria: Community structure and habitat modification by acid extremophiles P. C. Bennett and L. Stern, Dept. of Geological Sciences, University of Texas The Earth's subsurface contains innumerable extreme habitats that are occupied solely by microorganisms that survive by manipulating chemical forms of energy and altering their geologic surroundings to scavenge nutrients. This project will investigate the geology, geochemistry, and microbiology of a sulfidic cave system in Wyoming, and characterize the interaction between an acid-generating microbial population and the surrounding rocks. The Kane Caves, WY have a diverse microbial community that consumes hydrogen sulfide as a source of energy, while producing sulfuric acid as the waste product. The produced acid chemically dissolves the surrounding carbonate rock to produce a cave, a potential modern analog for the formation of Carlsbad Caverns. The goals of this project are to characterize the importance of these unusual microbial populations in the production of acid, and the carbon and sulfur cycles in this chemically based subsurface ecosystem. PIs will also identify the source of fundamental inorganic nutrients, measure the rate of carbonate dissolution and cave expansion, and characterize the influence of changing hydrologic conditions on the microbial community. These results will be used to develop methods for identifying the geologic fingerprints of chemical autotrophy, extremely acid environments, and microbial acid speleogenesis.