HR: 1340h
AN: B53C-1001    [Abstracts]
TI: The Microbial Karst Sulfuric Acid Dynamo
AU: * Lyon, E
EM: ezralyon@yahoo.com
AF: Pennsylvania State University, Department of Geosciences, University Park, PA 16802 United States
AU: Meyer, K
EM: kmeyer@geosc.psu.edu
AF: Pennsylvania State University, Department of Geosciences, University Park, PA 16802 United States
AU: Koffman, B
EM: besskoffman@hotmail.com
AF: Carleton College, Geology Department, Northfield, MN 55057 United States
AU: Galdenzi, S
EM: sagalde@tin.it
AF: Instituto Italiano di Speleologia, Sezione di Frasassi, Genga, AN 60040 Italy
AU: Macalady, J
EM: jmacalad@geosc.psu.edu
AF: Pennsylvania State University, Department of Geosciences, University Park, PA 16802 United States
AB: The original model for sulfuric acid speleogenesis attributes limestone dissolution to the oxidation of gaseous H2S to sulfuric acid on limestone cave walls (Egemeier 1981). This model has recently been reexamined in Lower Kane Cave, Wyoming (USA), where the most intense limestone dissolution appears to be the result of microbial colonization of limestone surfaces below the water table (Engel et al. 2004). In contrast, sulfuric acid speleogenesis in the Frasassi Caves (Italy) is equally intense above and below the water table, and is mediated not only by sulfur-oxidizing bacteria but by a complex community of sulfur cycling microorganisms including diverse sulfate-reducing bacteria. The sulfate-reducing bacteria were identified in 16S rDNA clone libraries from both cave walls and cave stream biofilms. These findings suggest a new model for sulfuric acid speleogenesis in which a full range of oxidants and reductants available to indigenous sulfur-cycling microbial communities control the extent of sulfur recycling and sulfuric acid production at limestone surfaces.
DE: 9335 Europe
DE: 1886 Weathering (1625)
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting