@article{MitzscherlingHornWinterfeldetal.2019,
  author    = {Mitzscherling, Julia and Horn, Fabian and Winterfeld, Maria and Mahler, Linda and Kallmeyer, Jens and Overduin, Pier Paul and Schirrmeister, Lutz and Winkel, Matthias and Grigoriev, Mikhail N. and Wagner, Dirk and Liebner, Susanne},
  title     = {Microbial community composition and abundance after millennia of submarine permafrost warming},
  series = {Biogeosciences},
  volume    = {16},
  journal   = {Biogeosciences},
  number    = {19},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1726-4170},
  doi       = {10.5194/bg-16-3941-2019},
  pages     = {3941 -- 3958},
  year      = {2019},
  abstract  = {Warming of the Arctic led to an increase in permafrost temperatures by about 0.3 degrees C during the last decade. Permafrost warming is associated with increasing sediment water content, permeability, and diffusivity and could in the long term alter microbial community composition and abundance even before permafrost thaws. We studied the long-term effect (up to 2500 years) of submarine permafrost warming on microbial communities along an onshore-offshore transect on the Siberian Arctic Shelf displaying a natural temperature gradient of more than 10 degrees C. We analysed the in situ development of bacterial abundance and community composition through total cell counts (TCCs), quantitative PCR of bacterial gene abundance, and amplicon sequencing and correlated the microbial community data with temperature, pore water chemistry, and sediment physicochemical parameters. On timescales of centuries, permafrost warming coincided with an overall decreasing microbial abundance, whereas millennia after warming microbial abundance was similar to cold onshore permafrost. In addition, the dissolved organic carbon content of all cores was lowest in submarine permafrost after millennial-scale warming. Based on correlation analysis, TCC, unlike bacterial gene abundance, showed a significant rank-based negative correlation with increasing temperature, while bacterial gene copy numbers showed a strong negative correlation with salinity. Bacterial community composition correlated only weakly with temperature but strongly with the pore water stable isotopes delta O-18 and delta D, as well as with depth. The bacterial community showed substantial spatial variation and an overall dominance of Actinobacteria, Chloroflexi, Firmicutes, Gemmatimonadetes, and Proteobacteria, which are amongst the microbial taxa that were also found to be active in other frozen permafrost environments. We suggest that, millennia after permafrost warming by over 10 degrees C, microbial community composition and abundance show some indications for proliferation but mainly reflect the sedimentation history and paleoenvironment and not a direct effect through warming.},
  language  = {en}
}
@article{VuilleminHornFrieseetal.2018,
  author    = {Vuillemin, Aurele and Horn, Fabian and Friese, Andre and Winkel, Matthias and Alawi, Mashal and Wagner, Dirk and Henny, Cynthia and Orsi, William D. and Crowe, Sean A. and Kallmeyer, Jens},
  title     = {Metabolic potential of microbial communities from ferruginous sediments},
  series = {Environmental microbiology},
  volume    = {20},
  journal   = {Environmental microbiology},
  number    = {12},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {1462-2912},
  doi       = {10.1111/1462-2920.14343},
  pages     = {4297 -- 4313},
  year      = {2018},
  abstract  = {Ferruginous (Fe-rich, SO4-poor) conditions are generally restricted to freshwater sediments on Earth today, but were likely widespread during the Archean and Proterozoic Eons. Lake Towuti, Indonesia, is a large ferruginous lake that likely hosts geochemical processes analogous to those that operated in the ferruginous Archean ocean. The metabolic potential of microbial communities and related biogeochemical cycling under such conditions remain largely unknown. We combined geochemical measurements (pore water chemistry, sulfate reduction rates) with metagenomics to link metabolic potential with geochemical processes in the upper 50 cm of sediment. Microbial diversity and quantities of genes for dissimilatory sulfate reduction (dsrAB) and methanogenesis (mcrA) decrease with increasing depth, as do rates of potential sulfate reduction. The presence of taxa affiliated with known iron- and sulfate-reducers implies potential use of ferric iron and sulfate as electron acceptors. Pore-water concentrations of acetate imply active production through fermentation. Fermentation likely provides substrates for respiration with iron and sulfate as electron donors and for methanogens that were detected throughout the core. The presence of ANME-1 16S and mcrA genes suggests potential for anaerobic methane oxidation. Overall our data suggest that microbial community metabolism in anoxic ferruginous sediments support coupled Fe, S and C biogeochemical cycling.},
  language  = {en}
}
@article{NagakuraSchubertWagneretal.2022,
  author    = {Nagakura, Toshiki and Schubert, Florian and Wagner, Dirk and Kallmeyer, Jens},
  title     = {Biological sulfate reduction in deep subseafloor sediment of Guaymas Basin},
  series = {Frontiers in microbiology},
  volume    = {13},
  journal   = {Frontiers in microbiology},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  organization    = {IODP Exp 385 Shipboard Sci Party},
  issn      = {1664-302X},
  doi       = {10.3389/fmicb.2022.845250},
  pages     = {12},
  year      = {2022},
  abstract  = {Sulfate reduction is the quantitatively most important process to degrade organic matter in anoxic marine sediment and has been studied intensively in a variety of settings. Guaymas Basin, a young marginal ocean basin, offers the unique opportunity to study sulfate reduction in an environment characterized by organic-rich sediment, high sedimentation rates, and high geothermal gradients (100-958 degrees C km(-1)). We measured sulfate reduction rates (SRR) in samples taken during the International Ocean Discovery Program (IODP) Expedition 385 using incubation experiments with radiolabeled (SO42-)-S-35 carried out at in situ pressure and temperature. The highest SRR (387 nmol cm(-3) d(-1)) was recorded in near-surface sediments from Site U1548C, which had the steepest geothermal gradient (958 degrees C km(-1)). At this site, SRR were generally over an order of magnitude higher than at similar depths at other sites (e.g., 387-157 nmol cm(-3) d(-1) at 1.9 mbsf from Site U1548C vs. 46-1.0 nmol cm(-3) d(-1) at 2.1 mbsf from Site U1552B). Site U1546D is characterized by a sill intrusion, but it had already reached thermal equilibrium and SRR were in the same range as nearby Site U1545C, which is minimally affected by sills. The wide temperature range observed at each drill site suggests major shifts in microbial community composition with very different temperature optima but awaits confirmation by molecular biological analyses. At the transition between the mesophilic and thermophilic range around 40 degrees C-60 degrees C, sulfate-reducing activity appears to be decreased, particularly in more oligotrophic settings, but shows a slight recovery at higher temperatures.},
  language  = {en}
}
@article{FischerHrubcovaDahmetal.2022,
  author    = {Fischer, Tom{\´a}š and Hrubcova, Pavla and Dahm, Torsten and Woith, Heiko and Vylita, Tom{\´a}š and Ohrnberger, Matthias and Vlček, Josef and Horalek, Josef and Dedecek, Petr and Zimmer, Martin and Lipus, Martin P. and Pierdominici, Simona and Kallmeyer, Jens and Kr{\"u}ger, Frank and Hannemann, Katrin and Korn, Michael and Kaempf, Horst and Reinsch, Thomas and Klicpera, Jakub and Vollmer, Daniel and Daskalopoulou, Kyriaki},
  title     = {ICDP drilling of the Eger Rift observatory},
  series = {Scientific drilling : reports on deep earth sampling and monitoring},
  volume    = {31},
  journal   = {Scientific drilling : reports on deep earth sampling and monitoring},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1816-8957},
  doi       = {10.5194/sd-31-31-2022},
  pages     = {31 -- 49},
  year      = {2022},
  abstract  = {The new in situ geodynamic laboratory established in the framework of the ICDP Eger project aims to develop the most modern, comprehensive, multiparameter laboratory at depth for studying earthquake swarms, crustal fluid flow, mantle-derived CO2 and helium degassing, and processes of the deep biosphere. In order to reach a new level of high-frequency, near-source and multiparameter observation of earthquake swarms and related phenomena, such a laboratory comprises a set of shallow boreholes with high-frequency 3-D seismic arrays as well as modern continuous real-time fluid monitoring at depth and the study of the deep biosphere. This laboratory is located in the western part of the Eger Rift at the border of the Czech Republic and Germany (in the West Bohemia-Vogtland geodynamic region) and comprises a set of five boreholes around the seismoactive zone. To date, all monitoring boreholes have been drilled. This includes the seismic monitoring boreholes S1, S2 and S3 in the crystalline units north and east of the major Nov{\´y} Kostel seismogenic zone, borehole F3 in the Hartoušov mofette field and borehole S4 in the newly discovered Bažina maar near Lib{\´a}. Supplementary borehole P1 is being prepared in the Neualbenreuth maar for paleoclimate and biological research. At each of these sites, a borehole broadband seismometer will be installed, and sites S1, S2 and S3 will also host a 3-D seismic array composed of a vertical geophone chain and surface seismic array. Seismic instrumenting has been completed in the S1 borehole and is in preparation in the remaining four monitoring boreholes. The continuous fluid monitoring site of Hartoušov includes three boreholes, F1, F2 and F3, and a pilot monitoring phase is underway. The laboratory also enables one to analyze microbial activity at CO2 mofettes and maar structures in the context of changes in habitats. The drillings into the maar volcanoes contribute to a better understanding of the Quaternary paleoclimate and volcanic activity.},
  language  = {en}
}
@article{FischerHrubcovaDahmetal.2022,
  author    = {Fischer, Tomas and Hrubcova, Pavla and Dahm, Torsten and Woith, Heiko and Vylita, Tomas and Ohrnberger, Matthias and Vlcek, Josef and Horalek, Josef and Dedecek, Petr and Zimmer, Martin and Lipus, Martin P. and Pierdominici, Simona and Kallmeyer, Jens and Kr{\"u}ger, Frank and Hannemann, Katrin and Korn, Michael and K{\"a}mpf, Horst and Reinsch, Thomas and Klicpera, Jakub and Vollmer, Daniel and Daskalopoulou, Kyriaki},
  title     = {ICDP drilling of the Eger Rift observatory},
  series = {Scientific Drilling},
  volume    = {31},
  journal   = {Scientific Drilling},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1816-8957},
  doi       = {10.5194/sd-31-31-2022},
  pages     = {31 -- 49},
  year      = {2022},
  abstract  = {The new in situ geodynamic laboratory established in the framework of the ICDP Eger project aims to develop the most modern, comprehensive, multiparameter laboratory at depth for studying earthquake swarms, crustal fluid flow, mantle-derived CO2 and helium degassing, and processes of the deep biosphere. In order to reach a new level of high-frequency, near-source and multiparameter observation of earthquake swarms and related phenomena, such a laboratory comprises a set of shallow boreholes with high-frequency 3-D seismic arrays as well as modern continuous real-time fluid monitoring at depth and the study of the deep biosphere. This laboratory is located in the western part of the Eger Rift at the border of the Czech Republic and Germany (in the West Bohemia-Vogtland geodynamic region) and comprises a set of five boreholes around the seismoactive zone. To date, all monitoring boreholes have been drilled. This includes the seismic monitoring boreholes S1, S2 and S3 in the crystalline units north and east of the major Novy Kostel seismogenic zone, borehole F3 in the Hartousov mofette field and borehole S4 in the newly discovered Bazina maar near Liba. Supplementary borehole P1 is being prepared in the Neualbenreuth maar for paleoclimate and biological research. At each of these sites, a borehole broadband seismometer will be installed, and sites S1, S2 and S3 will also host a 3-D seismic array composed of a vertical geophone chain and surface seismic array. Seismic instrumenting has been completed in the S1 borehole and is in preparation in the remaining four monitoring boreholes. The continuous fluid monitoring site of Hartousov includes three boreholes, F1, F2 and F3, and a pilot monitoring phase is underway. The laboratory also enables one to analyze microbial activity at CO2 mofettes and maar structures in the context of changes in habitats. The drillings into the maar volcanoes contribute to a better understanding of the Quaternary paleoclimate and volcanic activity.},
  language  = {en}
}