HR: 0800h
AN: B31C-0510    [Abstracts]
TI: Geomicrobiology of Carbonate Mounds in the Gulf of Cadiz off Morocco: Biogeochemistry, Mineralogy and Microbial Community Composition
AU: * Templer, S P
EM: stefanie.templer@erdw.ethz.ch
AF: ETH Zurich, Geological Institute Universitaetsstrasse 16, Zurich, 8092, Switzerland
AU: Stadnitskaia, A
EM: alina@nioz.nl
AF: NIOZ, P.O. Box 59, Den Burg, 1790 AB, Netherlands
AU: Maignien, L
EM: lois.maignien@UGent.be
AF: ETH Zurich, Geological Institute Universitaetsstrasse 16, Zurich, 8092, Switzerland
AU: Maignien, L
EM: lois.maignien@UGent.be
AF: Ghent University, LabMET Coupure Links 653, Ghent, 9000, Belgium
AU: Vasconcelos, C
EM: crisogono.vasconcelos@erdw.ethz.ch
AF: ETH Zurich, Geological Institute Universitaetsstrasse 16, Zurich, 8092, Switzerland
AU: McKenzie, J A
EM: sediment@erdw.ethz.ch
AF: ETH Zurich, Geological Institute Universitaetsstrasse 16, Zurich, 8092, Switzerland
AB: Carbonate mud mounds, found in marine environments from shallow- to deep-water settings, span from Proterozoic to recent times. Mound building seems to be a fundamental but still enigmatic strategy for life. Various arguments suggest that microorganisms are playing an important role in the reef development, biodiversity and mound formation. Therefore, it is important to evaluate the microbial mediated processes of carbonate precipitation. The Pen Duick Escarpment off Morocco consists of recent carbonate mounds in water depths of 500-600 m, flanked by giant mud volcanoes. Subsequent cruises have confirmed the colonization by dominantly lifeless cold- water corals and have unveiled extensive fields of seep-related carbonates in off-reef regions. Three (from 350 to 640 cm long) piston cores, coming from different sites on these juvenile mounds, were sampled and analyzed for mineralogy, stable isotopes composition, geochemistry, and microbial communities. In order to define the primary microbial community involved in carbonate precipitation, we did direct culturing, DNA isolation and PCR analysis of functional genes, including 16S rRNA gene analysis. Most of the sediment comprises pelagic calcite (coccoliths), detrital quartz and authigenic dolomite, often observed encasing coccoliths. Stable carbon isotope values of the bulk carbonate range from -7 to -15‰ indicating the involvement of microbes in the production of bicarbonate ions. In this paper, we will show and discuss multidisciplinary data obtained after several cruises aimed to elucidate the impact of microorganisms on the construction of these carbonate mounds. The special emphasis in this research will be on the correlation between microbial ecosystems and their metabolic influence on mineral formation and diagenesis.
DE: 0419 Biomineralization
DE: 0424 Biosignatures and proxies
DE: 0448 Geomicrobiology
DE: 0463 Microbe/mineral interactions
SC: Biogeosciences [B]
MN: 2007 Fall Meeting