HR: 09:45h
AN: NB51B-06    [Abstracts]
TI: Microbial Populations in Lithifying and Non-lithifying Microbial Mat Systems: Community Interactions with Chemical and Physical Ecology
AU: * Baumgartner, L K
EM: laura.baumgartner@uconn.edu
AF: University of Connecticut Marine Sciences, 1080 Shennecossett Rd., Groton, CT 80227 United States
AU: Vischer, P T
EM: pieter.visscher@uconn.edu
AF: University of Connecticut Marine Sciences, 1080 Shennecossett Rd., Groton, CT 80227 United States
AU: Dupraz, C
EM: christophe.dupraz@unine.ch
AF: University of Neuchatel Institute of Geology, Rue Emile-Argand 11, 2007 , Neuchatel, Switzerland
AU: Reid, R P
EM: preid@rsmas.miami.edu
AF: Rosenstiel School of Marine Science and Atmospheric Science, University of Miami, Marine Geology and Geophysics 4600 Rickenback Causeway, Miami, FL 33149 United States
AU: Buckley, D H
EM: dhb28@CORNELL.EDU
AF: Cornell University Department of Crop and Soil Sciences, 705 Bradfield Hall , Ithaca, NY 14853 United States
AU: Spear, J R
EM: spearj@colorado.edu
AF: University of Colorado Molecular, Cellular, and Developmental Biology, 347 UCB, Boulder, CO 80309 United States
AU: Pace, N R
EM: Norman.Pace@Colorado.EDU
AF: University of Colorado Molecular, Cellular, and Developmental Biology, 347 UCB, Boulder, CO 80309 United States
AB: The precipitation of calcium carbonate in microbial mat systems such as stromatolites creates a geological record of life. We cannot read that record, however, without understanding the mechanism of precipitation and lithification (the consolidation of loose sediment grains into solid rock). Several different groups of mat bacteria have been implicated in the precipitation and dissolution of calcium carbonate, most notably cyanobacteria, sulfate-reducing bacteria, aerobic heterotrophs, and sulfide-oxidizing bacteria. Through their metabolic activities, cyanobacteria and sulfate-reducing bacteria both facilitate precipitation, while heterotrophs and sulfide-oxidizing bacteria facilitate dissolution. These trends within the larger functional groups are further affected by within-group differences, such as the ability of some sulfate reducers to more fully oxidize carbon, which should also result in greater precipitation. Differential abilities within the microbial community may create the difference between mat systems that do and do not form lithified layers. Both the larger functional groups and the within-group changes are often phylogenetically predictable, and community analysis of lithifying and non-lithifying mat systems may provide some predictions as to which groups dominate lithification. Two research sites provide ideal study systems: a hypersaline lagoon in Eleuthera, Bahamas, where lithifying and non-lithifying mats coexist under similar physical and chemical environments, and the open marine stromatolites of Highborne Cay, Bahamas, which exhibit both lithifying and non-lithifying surfaces. The microbial communities of both microbial mat types from these two systems were analyzed to elucidate the population structure and examine differences between the communities. Given the very different mat systems growing under similar large-scale environments, the community structures are an interesting reflection of how microbes both affect and are affected by their environment.
DE: 0400 Biogeosciences
DE: 4803 Bacteria
DE: 4805 Biogeochemical cycles (1615)
DE: 4815 Ecosystems, structure and dynamics
DE: 4840 Microbiology
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly