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Reykjavík, Iceland

Krebs J.E.,Jet Propulsion Laboratory | Vaishampayan P.,Jet Propulsion Laboratory | Probst A.J.,University of Regensburg | Tom L.M.,Lawrence Berkeley National Laboratory | And 3 more authors.
Astrobiology | Year: 2014

Microbial community profiles of recently formed hot spring systems ranging in temperatures from 57 °C to 100 °C and pH values from 2 to 4 in Hverageroi (Iceland) were analyzed with PhyloChip G3 technology. In total, 1173 bacterial operational taxonomic units (OTUs) spanning 576 subfamilies and 38 archaeal OTUs covering 32 subfamilies were observed. As expected, the hyperthermophilic (∼100 C) spring system exhibited both low microbial biomass and diversity when compared to thermophilic (∼60 C) springs. Ordination analysis revealed distinct bacterial and archaeal diversity in geographically distinct hot springs. Slight variations in temperature (from 57 °C to 64 °C) within the interconnected pools led to a marked fluctuation in microbial abundance and diversity. Correlation and PERMANOVA tests provided evidence that temperature was the key environmental factor responsible for microbial community dynamics, while pH, H2S, and SO2 influenced the abundance of specific microbial groups. When archaeal community composition was analyzed, the majority of detected OTUs correlated negatively with temperature, and few correlated positively with pH. © Mary Ann Liebert, Inc. 2014. Source


Cockell C.S.,University of Edinburgh | Kelly L.C.,Open University Milton Keynes | Kelly L.C.,French National Institute for Agricultural Research | Marteinsson V.,Matis ohf. Food Safety
Geomicrobiology Journal | Year: 2013

A molecular biological analysis of Icelandic volcanic rocks of different compositions and glassiness revealed the presence of Actinobacteria as an abundant phylum. In outcrops of basaltic glass they were the dominant bacterial phylum. A diversity of Actinobacteria were cultured from the rocks on rock-agar plates showing that they are capable of growing on rock-derived nutrient sources and that many of the taxa identified by molecular methods are viable, potentially active members of the community. Laboratory batch-culture experiments using a Streptomyces isolate showed that it was capable of enhancing the release of major elements from volcanic rocks, including weathered basaltic glass, crystalline basalt and komatiite, when provided with a carbon source. Actinobacteria of a variety of other sub-orders were also capable of enhancing volcanic rock weathering, measured as Si release. However, most strains did not significantly increase the weathering of the silica-rich rock, obsidian. These data show that Actinobacteria can contribute to volcanic rock weathering and, therefore, the carbonate-silicate cycle. Given their ancient lineage, it is likely they have played a role in rock weathering for over two billion years. © 2013 Copyright Taylor and Francis Group, LLC. Source


Marteinsson V.,Matis ohf. Food Safety | Vaishampayan P.,Jet Propulsion Laboratory | Kviderova J.,Academy of Sciences of the Czech Republic | Kviderova J.,University of South Bohemia | And 16 more authors.
Life | Year: 2013

Existence of life in extreme environments has been known for a long time, and their habitants have been investigated by different scientific disciplines for decades. However, reports of multidisciplinary research are uncommon. In this paper, we report an interdisciplinary three-day field campaign conducted in the framework of the Coordination Action for Research Activities on Life in Extreme Environments (CAREX) FP7EU program, with participation of experts in the fields of life and earth sciences. In situ experiments and sampling were performed in a 20 m long hot springs system of different temperature (57 °C to 100 °C) and pH (2 to 4). Abiotic factors were measured to study their influence on the diversity. The CO2 and H2S concentration varied at different sampling locations in the system, but the SO2 remained the same. Four biofilms, mainly composed by four different algae and phototrophic protists, showed differences in photosynthetic activity. Varying temperature of the sampling location affects chlorophyll fluorescence, not only in the microbial mats, but plants (Juncus), indicating selective adaptation to the environmental conditions. Quantitative polymerase chain reaction (PCR), DNA microarray and denaturing gradient gel electrophoresis (DGGE)-based analysis in laboratory showed the presence of a diverse microbial population. Even a short duration (30 h) deployment of a micro colonizer in this hot spring system led to colonization of microorganisms based on ribosomal intergenic spacer (RISA) analysis. Polyphasic analysis of this hot spring system was possible due to the involvement of multidisciplinary approaches. © 2013 by the authors; licensee MDPI, Basel, Switzerland. Source

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