HR: 0800h
AN: B51B-0380    [Abstracts]
TI: Microbial Biomass and Community Structure of a Stromatolite from an Acid Mine Drainage System in Western Indiana
AU: * Fang, J
EM: jsfang@iastate.edu
AF: Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA 50011, United States
AU: Hasiotis, S T
EM: hasiotis@ku.edu
AF: Department of Geology and Natural History Museum and Biodiversity Research Center, 1475 Jayhawk Blvd., University of Kansas, Lawrence, KS 66045, United States
AU: Das Gupta, S
EM: shamik@iastate.edu
AF: Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA 50011, United States
AU: Brake, S S
EM: sbrake@isugw.indstate.edu
AF: Department of Geography, Geology and Anthropology, Indiana State University, Terre Haute, IN 47809, United States
AU: Bazylinski, D A
EM: dennis.bazylinski@unlv.edu
AF: School of Life Sciences, University of Nevada, Las Vegas 4505 Maryland Parkway, Las Vegas, NV 89154, United States
AB: Lipids extracted to determine the microbial biomass and community structure of an Fe-rich stromatolite from acid mine drainage (AMD) at the Green Valley coal mine site (GVS) in western Indiana correlate well with layers in the laminated stromatolite. The biomass of the top layer of the stromatolite was dominated by phototrophic organisms constituting 83% of the total biomass. Biomass of the lower layers was dominated by prokaryotic microorganisms. The presence of terminal methyl-branched fatty acids and mid methyl-branched fatty acids suggests the presence of Gram-positive and sulfate-reducing bacteria, respectively. Fungi appear to also be an important part of the AMD microbial communities as suggested by sterol profiles and the presence of polyunsaturated fatty acids. Hydroxy fatty acids and C₁₉ cyclopropane fatty acids were also detected and likely originated from acid-producing, acidophilic bacteria. The presence of Archaea is indicated by abundant phospholipid ether-linked isoprenoid hydrocarbons (phytane and phytadienes). The AMD Fe-rich stromatolites at GVS, thus, appear to be formed by interactions of microbial communities composed of all three domains of life; Archaea, Bacteria, and Eukarya. Identification of microeukaryote-dominated stromatolites verifies the prominent role these organisms play in the formation and preservation of these structures. In addition, the production of oxygen through photosynthesis by these organisms in AMD systems may be important for retrodicting the interaction of microbial communities in Precambrian environments in the production of microbially mediated sedimentary structures and oxygenation of Earth's early atmosphere.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0424 Biosignatures and proxies
DE: 0448 Geomicrobiology
DE: 0456 Life in extreme environments
DE: 0463 Microbe/mineral interactions
SC: Biogeosciences [B]
MN: 2007 Fall Meeting