HR: 1340h
AN: OS43A-0992    [Abstracts]
TI: Diversity of Microorganisms Associated With low Temperature Iron Deposits at the 71°N Hydrothermal Vent Field Along the Arctic Mid-Ocean Ridge
AU: * Ovreas, L
EM: lise.ovreas@bio.uib.no
AF: Centre for Geobiology, University of Bergen Allegaten 41, Bergen, N-5020, Norway
AU: * Ovreas, L
EM: lise.ovreas@bio.uib.no
AF: Department of Biology, University of Bergen Jahnebakken 5, Bergen, N-5020, Norway
AU: Johannessen, T
EM: torill.nilsen@bio.uib.no
AF: Centre for Geobiology, University of Bergen Allegaten 41, Bergen, N-5020, Norway
AU: Johannessen, T
EM: torill.nilsen@bio.uib.no
AF: Department of Biology, University of Bergen Jahnebakken 5, Bergen, N-5020, Norway
AU: Jorgensen, S
EM: steffen.jorgensen@cipr.uib.no
AF: Centre for Geobiology, University of Bergen Allegaten 41, Bergen, N-5020, Norway
AU: Jorgensen, S
EM: steffen.jorgensen@cipr.uib.no
AF: Department of Biology, University of Bergen Jahnebakken 5, Bergen, N-5020, Norway
AU: Thorseth, I H
EM: ingunn.thorseth@geo.uib.no
AF: Department of Biology, University of Bergen Jahnebakken 5, Bergen, N-5020, Norway
AU: Thorseth, I H
EM: ingunn.thorseth@geo.uib.no
AF: Department of Earth Science, University of Bergen Allegaten 41, Bergen, N-5020, Norway
AU: Pedersen, R B
EM: rolf.pedersen@geo.uib.no
AF: Department of Biology, University of Bergen Jahnebakken 5, Bergen, N-5020, Norway
AU: Pedersen, R B
EM: rolf.pedersen@geo.uib.no
AF: Department of Earth Science, University of Bergen Allegaten 41, Bergen, N-5020, Norway
AB: Rust coloured mounds and chimney-like deposits of the newly discovered71°N hydrothermal vent fields at the south-western part of the Mohns Ridge have been investigated. Iron is the fourth most abundant element in the Earth's crust and thus represents one of the most abundant redox active metals widely available for microbial energy generation. Microbial Fe-oxidation is a widespread process in the deep-sea environments, but only recently have studies begun to elucidate these processes and describe the phylogenetic and physiological diversity of the microbial communities that mediate them. Therefore studying the process by which iron is oxidised and how this influence these cold deep-sea communities is of significant importance. We have studied the microbial communities present in these low-temperature rust coloured deposits in order to elucidate the phylogenetic and physiological diversity of the microbial populations inhabiting these deep-sea environments. Polyphasic characterisations by using geochemical and biological analyses have been performed. The deposited material has a highly porous microtexture of branching, twisted filaments resembling stalks of the iron- oxidising Gallionella sp, but numerous other unidentified filamentous structures were also found to be present. Phylogenetic analysis of clone libraries has so far demonstrated that the bacterial community is dominated by members of the Proteobacteria, Planctomycetes and Chloroflexi. The archaeal community consists of both Crenarchaeota and Euryarchaeota. The Crenarchaeota sequences affiliates with other reported uncultivated Deep-Sea archaeal sequences. To further investigate the ecological impact of these iron mounds and their interaction with microorganisms cultivation experiments have been applied. We are specifically focusing on enrichment of iron oxidizing bacteria. Preliminary results indicates that iron oxidizers related to the newly described Mariprofundus ferrooxidans as well as iron reducers related to Rhodoferax ferrireducens are present in these environments, but we have not yet been able to obtain pure isolates form this site. Strains isolated from these systems will provide an opportunity to explore the phylogenetic diversity of neutrophilic Fe metabolism and to establish model systems for molecular metabolic studies. Description of microbial communities existing under such characteristic sub-seafloor environments is important when understanding the role these communities play in the major biochemical processes.
DE: 3000 MARINE GEOLOGY AND GEOPHYSICS
DE: 3017 Hydrothermal systems (0450, 1034, 3616, 4832, 8135, 8424)
DE: 3035 Midocean ridge processes
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting