Rolf Birger Pedersen

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The Arctic Mid-Ocean Ridge (AMOR) represents one of the most slow-spreading ridge systems on Earth. Previous attempts to locate hydrothermal vent fields and unravel the nature of venting, as well as the provenance of vent fauna at this northern and insular termination of the global ridge system, have been unsuccessful. Here, we report the first discovery of(More)
Microbial communities and their associated metabolic activity in marine sediments have a profound impact on global biogeochemical cycles. Their composition and structure are attributed to geochemical and physical factors, but finding direct correlations has remained a challenge. Here we show a significant statistical relationship between variation in(More)
Microbial communities inhabiting recent (< or =1 million years old; Ma) seafloor basalts from the Arctic spreading ridges were analyzed using traditional enrichment culturing methods in combination with culture-independent molecular phylogenetic techniques. Fragments of 16S rDNA were amplified from the basalt samples by polymerase chain reaction, and(More)
Water-rock interactions in ultramafic lithosphere generate reduced chemical species such as hydrogen that can fuel subsurface microbial communities. Sampling of this environment is expensive and technically demanding. However, highly accessible, uplifted oceanic lithospheres emplaced onto continental margins (ophiolites) are potential model systems for(More)
Hydrothermal vent systems harbor rich microbial communities ranging from aerobic mesophiles to anaerobic hyperthermophiles. Among these, members of the archaeal domain are prevalent in microbial communities in the most extreme environments, partly because of their temperature-resistant and robust membrane lipids. In this study, we use geochemical and(More)
The Epsilonproteobacteria, including members of the genus Sulfurovum, are regarded as important primary producers in hydrothermal systems. However, their in situ gene expression in this habitat has so far not been investigated. We report a metatranscriptomic analysis of a Sulfurovum-dominated biofilm from one of the chimneys at the Loki's Castle(More)
The Mid-Cayman spreading centre is an ultraslow-spreading ridge in the Caribbean Sea. Its extreme depth and geographic isolation from other mid-ocean ridges offer insights into the effects of pressure on hydrothermal venting, and the biogeography of vent fauna. Here we report the discovery of two hydrothermal vent fields on the Mid-Cayman spreading centre.(More)
A novel thermophilic and lithoautotrophic sulfate-reducing archaeon was isolated from black rust formed on the steel surface of a borehole observatory (CORK 1026B) retrieved during IODP Expedition 301 on the eastern flank of Juan de Fuca Ridge, eastern Pacific Ocean. Cells of the strain were lobe-shaped or triangular. The optimum temperature, pH and NaCl(More)
A novel thermophilic member of the family Thermaceae, designated strain 2M70-1(T), was isolated from the wall of an active white smoker chimney collected in the Soria Moria vent field at 71 °N in the Norwegian-Greenland Sea. Cells of the strain were Gram-negative, non-motile rods. Growth was observed at 37-75 °C (optimum 65 °C), at pH 6-8 (optimum pH 7.3)(More)
Deep-sea hydrothermal vents are unique environments on Earth, as they host chemosynthetic ecosystems fuelled by geochemical energy with chemolithoautotrophic microorganisms at the basis of the food webs. Whereas discrete high-temperature venting systems have been studied extensively, the microbiotas associated with low-temperature diffuse venting are not(More)