@article {ISI:000331366700001,
	title = {{Microbial habitat connec ivity across spatial scales and hydrothermal temperature gradients at Guaymas Basin}},
	journal = {FRONTIERS IN MICROBIOLOGY},
	volume = {4},
	year = {2013},
	month = {jul},
	type = {Article},
	abstract = {The Guaymas Basin (Gulf of California) hydrothermal vent area is known as a dynamic and hydrothermally vented sedimentary system, where the advection and production of a variety of different metabolic substrates support a high microbial diversity and activity in the seafloor. The main objective of our study was to explore the role of temperature and other environmental factors on community diversity, such as the presence of microbial mats and seafloor bathymetry within one hydrothermally vented field of 200 x 250 m dimension. In this field, temperature increased strongly with sediment depth reaching the known limit of life within a few decimeters. Potential sulfate reduction rate as a key community activity parameter was strongly affected by in situ temperature and sediment depth, declining from high rates of 1-5 jimol m1-1 d-1 at the surface to the detection limit below 5 cm sediment depth, despite the presence of sulfate and hydrocarbons. Automated Ribosomal lntergenic Spacer Analysis yielded a high-resolution fingerprint of the dominant members of the bacterial community. Our analyses showed strong temperature and sediment depth effects on bacterial cell abundance and Operational Taxonomic Units (OTUs) number, both declining by more than one order of magnitude below the top 5 cm of the sediment surface. Another fraction of the variation in diversity and community structure was explained by differences in the local bathymetry and spatial position within the vent field. Nevertheless, more than 80{\%} of all detected OTUs were shared among the different temperature realms and sediment depths, after being classified as cold (T {\textless} 10 C), medium (10 C {\textless} T {\textless} 40 C) or hot (T {\textgreater} 40 C) temperature conditions, with significant OTU overlap with the richer surface communities. Overall, this indicates a high connectivity of benthic bacterial habitats in this dynamic and heterogeneous marine ecosystem influenced by strong hydrothermalism.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {1664-302X},
	doi = {10.3389/fmicb.2013.00207},
	author = {Meyer, Stefanie and Wegener, Gunter and Lloyd, Karen G and Teske, Andreas and Boetius, Antje and Ramette, Alban}
}
@article {ISI:000302950700011,
	title = {{Anaerobic oxidation of methane at different temperature regimes in Guaymas Basin hydrothermal sediments}},
	journal = {ISME JOURNAL},
	volume = {6},
	number = {5},
	year = {2012},
	month = {may},
	pages = {1018{\textendash}1031},
	type = {Article},
	abstract = {Anaerobic oxidation of methane (AOM) was investigated in hydrothermal sediments of Guaymas Basin based on delta C-13 signatures of CH4, dissolved inorganic carbon and porewater concentration profiles of CH4 and sulfate. Cool, warm and hot in-situ temperature regimes (15-20 degrees C, 30-35 degrees C and 70-95 degrees C) were selected from hydrothermal locations in Guaymas Basin to compare AOM geochemistry and 16S ribosomal RNA (rRNA), mcrA and dsrAB genes of the microbial communities. 16S rRNA gene clone libraries from the cool and hot AOM cores yielded similar archaeal types such as Miscellaneous Crenarchaeotal Group, Thermoproteales and anaerobic methane-oxidizing archaea (ANME)-1; some of the ANME-1 archaea formed a separate 16S rRNA lineage that at present seems to be limited to Guaymas Basin. Congruent results were obtained by mcrA gene analysis. The warm AOM core, chemically distinct by lower porewater sulfide concentrations, hosted a different archaeal community dominated by the two deep subsurface archaeal lineages Marine Benthic Group D and Marine Benthic Group B, and by members of the Methanosarcinales including ANME-2 archaea. This distinct composition of the methane-cycling archaeal community in the warm AOM core was confirmed by mcrA gene analysis. Functional genes of sulfate-reducing bacteria and archaea, dsrAB, showed more overlap between all cores, regardless of the core temperature. 16S rRNA gene clone libraries with Euryarchaeota-specific primers detected members of the Archaeoglobus clade in the cool and hot cores. A V6-tag high-throughput sequencing survey generally supported the clone library results while providing high-resolution detail on archaeal and bacterial community structure. These results indicate that AOM and the responsible archaeal communities persist over a wide temperature range. The ISME Journal (2012) 6, 1018-1031; doi:10.1038/ismej.2011.164; published online 17 November 2011},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {1751-7362},
	doi = {10.1038/ismej.2011.164},
	author = {Biddle, Jennifer F and Cardman, Zena and Mendlovitz, Howard and Albert, Daniel B and Lloyd, Karen G and Boetius, Antje and Teske, Andreas}
}
@article {ISI:000299052400011,
	title = {{Thermophilic anaerobic oxidation of methane by marine microbial consortia}},
	journal = {ISME JOURNAL},
	volume = {5},
	number = {12},
	year = {2011},
	month = {dec},
	pages = {1946{\textendash}1956},
	type = {Article},
	abstract = {The anaerobic oxidation of methane (AOM) with sulfate controls the emission of the greenhouse gas methane from the ocean floor. AOM is performed by microbial consortia of archaea (ANME) associated with partners related to sulfate-reducing bacteria. In vitro enrichments of AOM were so far only successful at temperatures {\textless}= 25 degrees C; however, energy gain for growth by AOM with sulfate is in principle also possible at higher temperatures. Sequences of 16S rRNA genes and core lipids characteristic for ANME as well as hints of in situ AOM activity were indeed reported for geothermally heated marine environments, yet no direct evidence for thermophilic growth of marine ANME consortia was obtained to date. To study possible thermophilic AOM, we investigated hydrothermally influenced sediment from the Guaymas Basin. In vitro incubations showed activity of sulfate-dependent methane oxidation between 5 and 70 degrees C with an apparent optimum between 45 and 60 degrees C. AOM was absent at temperatures {\textgreater}= 75 degrees C. Long-term enrichment of AOM was fastest at 50 degrees C, yielding a 13-fold increase of methane-dependent sulfate reduction within 250 days, equivalent to an apparent doubling time of 68 days. The enrichments were dominated by novel ANME-1 consortia, mostly associated with bacterial partners of the deltaproteobacterial HotSeep-1 cluster, a deeply branching phylogenetic group previously found in a butane-amended 60 degrees C-enrichment culture of Guaymas sediments. The closest relatives (Desulfurella spp.; Hippea maritima) are moderately thermophilic sulfur reducers. Results indicate that AOM and ANME archaea could be of biogeochemical relevance not only in cold to moderate but also in hot marine habitats. The ISME Journal (2011) 5, 1946-1956; doi: 10.1038/ismej.2011.77; published online 23 June 2011},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {1751-7362},
	doi = {10.1038/ismej.2011.77},
	author = {Holler, Thomas and Widdel, Friedrich and Knittel, Katrin and Amann, Rudolf and Kellermann, Matthias Y and Hinrichs, Kai-Uwe and Teske, Andreas and Boetius, Antje and Wegener, Gunter}
}
