TY - JOUR A1 - Mrlina, Jan A1 - Kämpf, Horst A1 - Kroner, Corinna A1 - Mingram, Jens A1 - Stebich, Martina A1 - Brauer, Achim A1 - Geissler, Wolfram H. A1 - Kallmeyer, Jens A1 - Matthes, Heidrun A1 - Seidl, Michal T1 - Discovery of the first Quaternary maar in the Bohemian Massif, Central Europe, based on combined geophysical and geological surveys N2 - Based on results of previous investigations of tephra-tuff volcaniclastic deposits and a geophysical survey in the surroundings of the Zelezna hurka Quaternary volcano, West Bohemia, we performed detailed geophysical Surveys using gravimetry, magnetometry and electrical conductivity techniques. Striking anomalies were revealed in a morphological depression near Mytina, West Bohemia, as a strong evidence of the assumed maar-diatreme structure. The sharp isometric gravity low of -2.30 mGal, as well as the corresponding positive magnetic anomaly of 200 nT with a negative rim on its northern side indicate a steeply clipping geological body of low density and containing magnetic rocks/minerals. Magnetic survey also showed pronounced local anomalies outside the depression that can reflect relicts of the tephra rim of the maar. This geophysical evidence was then proven by an exploratory drilling near the centre of the gravity anomaly. Macroscopic on-site evaluation of the core, and more detailed sedimentological, petrochemical, palynological and microbiological laboratory analyses further confirmed the existence of a maar structure filled by 84 m of lake sediments reflecting a Succession of several warm and cold climatic periods. Results Of palynological analyses confirm the presence of a continuous palaeoclimate archive, with at least three successive warmer periods of most probably interstadial character from the upper Quaternary Saalian complex. Therefore. the recovered sediment sequence holds strong potential for in-depth palaeoclimate reconstruction and deep biosphere studies. At the bottom of the Mytina-1 (MY- 1) borehole (84-85.5 M), Country rock debris Was found, containing also volcanic bombs and lapilli. The discovered volcanic Structure is considered to be the first known Quaternary maar-diatreme volcano on the territory of the Bohemian Massif. Because of hidden active magmatic processes in combination with earthquake swarm seismicity ca. 20-30 km north of the Mytina maar, reconstruction of the palaeovolcanological evolution is important for evaluation of hazard potential of the NE and E Part of the Cheb Basin. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/03770273 U6 - https://doi.org/10.1016/j.jvolgeores.2009.01.027 SN - 0377-0273 ER - TY - JOUR A1 - Vuillemin, Aurele A1 - Horn, Fabian A1 - Friese, Andre A1 - Winkel, Matthias A1 - Alawi, Mashal A1 - Wagner, Dirk A1 - Henny, Cynthia A1 - Orsi, William D. A1 - Crowe, Sean A. A1 - Kallmeyer, Jens T1 - Metabolic potential of microbial communities from ferruginous sediments JF - Environmental microbiology N2 - 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. Y1 - 2018 U6 - https://doi.org/10.1111/1462-2920.14343 SN - 1462-2912 SN - 1462-2920 VL - 20 IS - 12 SP - 4297 EP - 4313 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Ijiri, Akira A1 - Inagaki, Fumio A1 - Kubo, Yusuke A1 - Adhikari, Rishi Ram A1 - Hattori, Shohei A1 - Hoshino, Tatsuhiko A1 - Imachi, Hiroyuki A1 - Kawagucci, Shinsuke A1 - Morono, Yuki A1 - Ohtomo, Yoko A1 - Ono, Shuhei A1 - Sakai, Sanae A1 - Takai, Ken A1 - Toki, Tomohiro A1 - Wang, David T. A1 - Yoshinaga, Marcos Y. A1 - Arnold, Gail L. A1 - Ashi, Juichiro A1 - Case, David H. A1 - Feseker, Tomas A1 - Hinrichs, Kai-Uwe A1 - Ikegawa, Yojiro A1 - Ikehara, Minoru A1 - Kallmeyer, Jens A1 - Kumagai, Hidenori A1 - Lever, Mark Alexander A1 - Morita, Sumito A1 - Nakamura, Ko-ichi A1 - Nakamura, Yuki A1 - Nishizawa, Manabu A1 - Orphan, Victoria J. A1 - Roy, Hans A1 - Schmidt, Frauke A1 - Tani, Atsushi A1 - Tanikawa, Wataru A1 - Terada, Takeshi A1 - Tomaru, Hitoshi A1 - Tsuji, Takeshi A1 - Tsunogai, Urumu A1 - Yamaguchi, Yasuhiko T. A1 - Yoshida, Naohiro T1 - Deep-biosphere methane production stimulated by geofluids in the Nankai accretionary complex JF - Science Advances Y1 - 2018 U6 - https://doi.org/10.1126/sciadv.aao4631 SN - 2375-2548 VL - 4 IS - 6 PB - American Assoc. for the Advancement of Science CY - Washington ER - TY - GEN A1 - Ijiri, Akira A1 - Inagaki, Fumio A1 - Kubo, Yusuke A1 - Adhikari, Rishi Ram A1 - Hattori, Shohei A1 - Hoshino, Tatsuhiko A1 - Imachi, Hiroyuki A1 - Kawagucci, Shinsuke A1 - Morono, Yuki A1 - Ohtomo, Yoko A1 - Ono, Shuhei A1 - Sakai, Sanae A1 - Takai, Ken A1 - Toki, Tomohiro A1 - Wang, David T. A1 - Yoshinaga, Marcos Y. A1 - Arnold, Gail L. A1 - Ashi, Juichiro A1 - Case, David H. A1 - Feseker, Tomas A1 - Hinrichs, Kai-Uwe A1 - Ikegawa, Yojiro A1 - Ikehara, Minoru A1 - Kallmeyer, Jens A1 - Kumagai, Hidenori A1 - Lever, Mark Alexander A1 - Morita, Sumito A1 - Nakamura, Ko-ichi A1 - Nakamura, Yuki A1 - Nishizawa, Manabu A1 - Orphan, Victoria J. A1 - Røy, Hans A1 - Schmidt, Frauke A1 - Tani, Atsushi A1 - Tanikawa, Wataru A1 - Terada, Takeshi A1 - Tomaru, Hitoshi A1 - Tsuji, Takeshi A1 - Tsunogai, Urumu A1 - Yamaguchi, Yasuhiko T. A1 - Yoshida, Naohiro T1 - Deep-biosphere methane production stimulated by geofluids in the Nankai accretionary complex T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Microbial life inhabiting subseafloor sediments plays an important role in Earth’s carbon cycle. However, the impact of geodynamic processes on the distributions and carbon-cycling activities of subseafloor life remains poorly constrained. We explore a submarine mud volcano of the Nankai accretionary complex by drilling down to 200 m below the summit. Stable isotopic compositions of water and carbon compounds, including clumped methane isotopologues, suggest that ~90% of methane is microbially produced at 16° to 30°C and 300 to 900 m below seafloor, corresponding to the basin bottom, where fluids in the accretionary prism are supplied via megasplay faults. Radiotracer experiments showed that relatively small microbial populations in deep mud volcano sediments (10 2 to 10 3 cells cm −3 ) include highly active hydrogenotrophic methanogens and acetogens. Our findings indicate that subduction-associated fluid migration has stimulated microbial activity in the mud reservoir and that mud volcanoes may contribute more substantially to the methane budget than previously estimated. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 802 KW - multiply-substituted isotopologues KW - marine subsurface sediments KW - carbon isotopic composition KW - submarine mud volcano KW - intact polar lipids KW - fore-arc basin KW - subseafloor sediments KW - microbial lipids KW - Cascadia margin KW - organic-acids Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427002 SN - 1866-8372 IS - 802 ER - TY - JOUR A1 - D'Hondt, Steven A1 - Spivack, Arthur J. A1 - Pockalny, Robert A1 - Ferdelman, Timothy G. A1 - Fischer, Jan P. A1 - Kallmeyer, Jens A1 - Abrams, Lewis J. A1 - Smith, David C. A1 - Graham, Dennis A1 - Hasiuk, Franciszek A1 - Schrum, Heather A1 - Stancin, Andrea M. T1 - Subseafloor sedimentary life in the South Pacific Gyre N2 - The low-productivity South Pacific Gyre (SPG) is Earth's largest oceanic province. Its sediment accumulates extraordinarily slowly (0.1-1 m per million years). This sediment contains a living community that is characterized by very low biomass and very low metabolic activity. At every depth in cored SPG sediment, mean cell abundances are 3 to 4 orders of magnitude lower than at the same depths in all previously explored subseafloor communities. The net rate of respiration by the subseafloor sedimentary community at each SPG site is 1 to 3 orders of magnitude lower than the rates at previously explored sites. Because of the low respiration rates and the thinness of the sediment, interstitial waters are oxic throughout the sediment column in most of this region. Consequently, the sedimentary community of the SPG is predominantly aerobic, unlike previously explored subseafloor communities. Generation of H-2 by radiolysis of water is a significant electron-donor source for this community. The per-cell respiration rates of this community are about 2 orders of magnitude higher (in oxidation/reduction equivalents) than in previously explored anaerobic subseafloor communities. Respiration rates and cell concentrations in subseafloor sediment throughout almost half of the world ocean may approach those in SPG sediment. Y1 - 2009 UR - http://www.pnas.org/ U6 - https://doi.org/10.1073/pnas.0811793106 SN - 0027-8424 ER - TY - JOUR A1 - Kallmeyer, Jens A1 - Pockalny, Rob A1 - D'Hondt, Steven T1 - Quantifying global subseafloor microbial abundance : method and implications Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/00167037 U6 - https://doi.org/10.1016/j.gca.2009.05.009 SN - 0016-7037 ER - TY - JOUR A1 - Kallmeyer, Jens A1 - Smith, David C. T1 - An improved electroelution method for separation of DNA from humic substances in marine sediment DNA extracts N2 - We present a method for the rapid and simple extraction of DNA from marine sediments using electroelution. It effectively separates DNA from compounds, including humic substances, that interfere with subsequent DNA quantification and amplification. After extraction of the DNA from the sediment into an aqueous solution, the crude sample is encased in 2% agarose gel and exposed to an electrical current, which draws the DNA out of the gel into a centrifugal filter vial. After electroelution, the sample is centrifuged to remove contaminants <= 100 000 Da. Recovery of DNA using this method is quantitative and does not discriminate on the basis of size, as determined using DNA standards and DNA extracts from environmental samples. Amplification of DNA is considerably improved due to removal of PCR inhibitors. For Archaea, only these purified extracts yielded PCR products. This method allows for the use of relatively large volumes of sediment and is particularly useful for sediments containing low biomass such as deeply buried marine sediments. It works with both organic-rich and -poor sediment, as well as with sediment where calcium carbonate is abundant and sediment where it is limited; consequently, adjustment of protocols is unnecessary for samples with very different organic and mineral contents. Y1 - 2009 UR - http://www3.interscience.wiley.com/cgi-bin/issn?DESCRIPTOR=PRINTISSN&VALUE=0168-6496 U6 - https://doi.org/10.1111/j.1574-6941.2009.00684.x SN - 0168-6496 ER - TY - JOUR A1 - Adhikari, Rishi Ram A1 - Kallmeyer, Jens T1 - Detection and quantification of microbial activity in the subsurface N2 - The subsurface harbors a large fraction of Earth's living biomass, forming complex microbial ecosystems. Without a profound knowledge of the ongoing biologically mediated processes and their reaction to anthropogenic changes it is difficult to assess the long-term stability and feasibility of any type of geotechnical utilization, as these influence subsurface ecosystems. Despite recent advances in many areas of subsurface microbiology, the direct quantification of turnover processes is still in its infancy, mainly due to the extremely low cell abundances. We provide an overview of the currently available techniques for the quantification of microbial turnover processes and discuss their specific strengths and limitations. Most techniques employed so far have focused on specific processes, e.g. sulfate reduction or methanogenesis. Recent studies show that processes that were previously thought to exclude each other can occur simultaneously, albeit at very low rates. Without the identification of the respective processes it is impossible to quantify total microbial activity. Even in cases where all simultaneously occurring processes can be identified, the typically very low rates prevent quantification. In many cases a simple measure of total microbial activity would be a better and more robust measure than assays for several specific processes. Enzyme or molecular assays provide a more general approach as they target key metabolic compounds. Depending on the compound targeted a broader spectrum of microbial processes can be quantified. The two most promising compounds are ATP and hydrogenase, as both are ubiquitous in microbes. Technical constraints limit the applicability of currently available ATP-assays for subsurface samples. A recently developed hydrogenase radiotracer assay has the potential to become a key tool for the quantification of subsurface microbial activity. Y1 - 2010 UR - http://www.sciencedirect.com/science/journal/00092819 U6 - https://doi.org/10.1016/j.chemer.2010.05.003 SN - 0009-2819 ER - TY - JOUR A1 - Glombitza, Clemens A1 - Stockhecke, Mona A1 - Schubert, Carsten J. A1 - Vetter, Alexandra A1 - Kallmeyer, Jens T1 - Sulfate reduction controlled by organic matter availability in deep sediment cores from the saline, alkaline Lake Van (Eastern Anatolia,Turkey) JF - Frontiers in microbiology N2 - As part of the International Continental Drilling Program deep lake drilling project Paleo Van, we investigated sulfate reduction (SR) in deep sediment cores of the saline, alkaline (salinity 21.4%0, alkalinity 155 m mEq-1, pH 9.81) Lake Van, Turkey. The cores were retrieved in the Northern Basin (NB) and at Ahlat Ridge (AR) and reached a maximum depth of 220 m. Additionally, 65-75 cm long gravity cores were taken at both sites. SR rates (SRR) were low (<22 nmol cm-3 day-1) compared to lakes with higher salinity and alkalinity, indicating that salinity and alkalinity are not limiting SR in Lake Van. Both sites differ significantly in rates and depth distribution of SR. In NB, SRR are up to 10 times higher than at AR. SR could be detected down to 19 mblf (meters below lake floor) at NB and down to 13 mblf at AR. Although SRR were lower at AR than at NB, organic matter (OM) concentrations were higher. In contrast, dissolved OM in the pore water at AR contained more macromolecular OM and less low molecular weight OM.VVe thus suggest, that OM content alone cannot be used to infer microbial activity at Lake Van but that quality of OM has an important impact as well. These differences suggest that biogeochemical processes in lacustrine sediments are reacting very sensitively to small variations in geological, physical, or chemical parameters over relatively short distances. KW - saline lake KW - alkaline lake KW - sulfate reduction KW - deep biosphere KW - organic matter Y1 - 2013 U6 - https://doi.org/10.3389/fmicb.2013.00209 SN - 1664-302X VL - 4 IS - 28 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Cockell, Charles S. A1 - Voytek, Mary A. A1 - Gronstal, Aaron L. A1 - Finster, Kai A1 - Kirshtein, Julie D. A1 - Howard, Kieren A1 - Reitner, Joachim A1 - Gohn, Gregory S. A1 - Sanford, Ward E. A1 - Horton, J. Wright A1 - Kallmeyer, Jens A1 - Kelly, Laura A1 - Powars, David S. T1 - Impact disruption and recovery of the deep subsurface biosphere JF - Astrobiology N2 - Although a large fraction of the world's biomass resides in the subsurface, there has been no study of the effects of catastrophic disturbance on the deep biosphere and the rate of its subsequent recovery. We carried out an investigation of the microbiology of a 1.76 km drill core obtained from the similar to 35 million-year-old Chesapeake Bay impact structure, USA, with robust contamination control. Microbial enumerations displayed a logarithmic downward decline, but the different gradient, when compared to previously studied sites, and the scatter of the data are consistent with a rnicrobiota influenced by the geological disturbances caused by the impact. Microbial abundance is low in buried crater-fill, ocean-resurge, and avalanche deposits despite the presence of redox couples for growth. Coupled with the low hydraulic conductivity, the data suggest the microbial community has not yet recovered from the impact similar to 35 million years ago. Microbial enumerations, molecular analysis of microbial enrichment cultures, and geochemical analysis showed recolonization of a deep region of impact-fractured rock that was heated to above the upper temperature limit for life at the time of impact. These results show how, by fracturing subsurface rocks, impacts can extend the depth of the biosphere. This phenomenon would have provided deep refugia for life on the more heavily bombarded early Earth, and it shows that the deeply fractured regions of impact craters are promising targets to study the past and present habitability of Mars. KW - Asteroid KW - Impacts KW - Subsurface biosphere KW - Subterranean environment KW - Geobiology Y1 - 2012 U6 - https://doi.org/10.1089/ast.2011.0722 SN - 1531-1074 VL - 12 IS - 3 SP - 231 EP - 246 PB - Liebert CY - New Rochelle ER - TY - JOUR A1 - Roy, Hans A1 - Kallmeyer, Jens A1 - Adhikari, Rishi Ram A1 - Pockalny, Robert A1 - Jorgensen, Bo Barker A1 - D'Hondt, Steven T1 - Aerobic microbial respiration in 86-million-year-old deep-sea red clay JF - Science N2 - Microbial communities can subsist at depth in marine sediments without fresh supply of organic matter for millions of years. At threshold sedimentation rates of 1 millimeter per 1000 years, the low rates of microbial community metabolism in the North Pacific Gyre allow sediments to remain oxygenated tens of meters below the sea floor. We found that the oxygen respiration rates dropped from 10 micromoles of O-2 liter(-1) year(-1) near the sediment-water interface to 0.001 micromoles of O-2 liter(-1) year(-1) at 30-meter depth within 86 million-year-old sediment. The cell-specific respiration rate decreased with depth but stabilized at around 10(-3) femtomoles of O-2 cell(-1) day(-1) 10 meters below the seafloor. This result indicated that the community size is controlled by the rate of carbon oxidation and thereby by the low available energy flux. Y1 - 2012 U6 - https://doi.org/10.1126/science.1219424 SN - 0036-8075 VL - 336 IS - 6083 SP - 922 EP - 925 PB - American Assoc. for the Advancement of Science CY - Washington ER - TY - JOUR A1 - Noah, Mareike A1 - Lappe, Michael A1 - Schneider, Beate A1 - Vieth-Hillebrand, Andrea A1 - Wilkes, Heinz A1 - Kallmeyer, Jens T1 - Tracing biogeochemical and microbial variability over a complete oil sand mining and recultivation process JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - Recultivation of disturbed oil sand mining areas is an issue of increasing importance. Nevertheless only little is known about the fate of organic matter, cell abundances and microbial community structures during oil sand processing, tailings management and initial soil development on reclamation sites. Thus the focus of this work is on biogeochemical changes of mined oil sands through the entire process chain until its use as substratum for newly developing soils on reclamation sites. Therefore, oil sand, mature fine tailings (MFTs) from tailings ponds and drying cells and tailings sand covered with peat-mineral mix (PMM) as part of land reclamation were analyzed. The sample set was selected to address the question whether changes in the above-mentioned biogeochemical parameters can be related to oil sand processing or biological processes and how these changes influence microbial activities and soil development. GC-MS analyses of oil-derived biomarkers reveal that these compounds remain unaffected by oil sand processing and biological activity. In contrast, changes in polycyclic aromatic hydrocarbon (PAH) abundance and pattern can be observed along the process chain. Especially naphthalenes, phenanthrenes and chrysenes are altered or absent on reclamation sites, Furthermore, root-bearing horizons on reclamation sites exhibit cell abundances at least ten times higher (10(8) to 10(9) cells g(-1)) than in oil sand and MFF samples (10(7) cells g(-1)) and show a higher diversity in their microbial community structure. Nitrate in the pore water and roots derived from the PMM seem to be the most important stimulants for microbial growth. The combined data show that the observed compositional changes are mostly related to biological activity and the addition of exogenous organic components (PMM), whereas oil extraction, tailings dewatering and compaction do not have significant influences on the evaluated compounds. Microbial community composition remains relatively stable through the entire process chain. (C) 2014 Elsevier B.V. All rights reserved. KW - Oil sands KW - Tailings ponds KW - Reclamation KW - PAN KW - Biomarker KW - Microbial community analysis Y1 - 2014 U6 - https://doi.org/10.1016/j.scitotenv.2014.08.020 SN - 0048-9697 SN - 1879-1026 VL - 499 SP - 297 EP - 310 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ciobanu, M. -C. A1 - Rabineau, M. A1 - Droz, L. A1 - Revillon, S. A1 - Ghiglione, J. -F. A1 - Dennielou, B. A1 - Jorry, S. -J. A1 - Kallmeyer, Jens A1 - Etoubleau, J. A1 - Pignet, P. A1 - Crassous, P. A1 - Vandenabeele-Trambouze, O. A1 - Laugier, J. A1 - Guegan, M. A1 - Godfroy, A. A1 - Alain, K. T1 - Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments JF - Biogeosciences N2 - An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG) and Halobacteria) within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the Betaproteobacteria group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea levee. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence analyses (CCA) showed that the availability of electron acceptors and the quality of electron donors (indicated by age) strongly influenced the community structure. In contrast, within the Gulf of Lion core, characterized by a homogeneous lithological structure of upper-slope environment, most detected groups were Bacteroidetes and, to a lesser extent, Betaproteobacteria. At both site, the detection of Betaproteobacteria coincided with increased terrestrial inputs, as confirmed by the geochemical measurements (Si, Sr, Ti and Ca). In the Gulf of Lion, geochemical parameters were also found to drive microbial community composition. Taken together, our data suggest that the palaeoenvironmental history of erosion and deposition recorded in the Western Mediterranean Sea sediments has left its imprint on the sedimentological context for microbial habitability, and then indirectly on structure and composition of the microbial communities during the late Quaternary. Y1 - 2012 U6 - https://doi.org/10.5194/bg-9-3491-2012 SN - 1726-4170 VL - 9 IS - 9 SP - 3491 EP - 3512 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Kallmeyer, Jens A1 - Grewe, Sina A1 - Glombitza, Clemens A1 - Kitte, J. Axel T1 - Microbial abundance in lacustrine sediments: a case study from Lake Van, Turkey JF - International journal of earth sciences N2 - The ICDP "PaleoVan" drilling campaign at Lake Van, Turkey, provided a long (> 100 m) record of lacustrine subsurface sedimentary microbial cell abundance. After the ICDP campaign at Potrok Aike, Argentina, this is only the second time deep lacustrine cell counts have been documented. Two sites were cored and revealed a strikingly similar cell distribution despite differences in organic matter content and microbial activity. Although shifted towards higher values, cell counts from Lake Potrok Aike, Argentina, reveal very similar distribution patterns with depth. The lacustrine cell count data are significantly different from published marine records; the most probable cause is differences in sedimentary organic matter composition with marine sediments containing a higher fraction of labile organic matter. Previous studies showed that microbial activity and abundance increase centimetres to metres around geologic interfaces. The finely laminated Lake Van sediment allowed studying this phenomenon on the microscale. We sampled at the scale of individual laminae, and in some depth intervals, we found large differences in microbial abundance between the different laminae. This small-scale heterogeneity is normally overlooked due to much larger sampling intervals that integrate over several centimetres. However, not all laminated intervals exhibit such large differences in microbial abundance, and some non-laminated horizons show large variability on the millimetre scale as well. The reasons for such contrasting observations remain elusive, but indicate that heterogeneity of microbial abundance in subsurface sediments has not been taken into account sufficiently. These findings have implications not just for microbiological studies but for geochemistry as well, as the large differences in microbial abundance clearly show that there are distinct microhabitats that deviate considerably from the surrounding layers. KW - Subsurface biosphere KW - Deep biosphere KW - Lake Van KW - Cell counts KW - Lacustrine sediment Y1 - 2015 U6 - https://doi.org/10.1007/s00531-015-1219-6 SN - 1437-3254 SN - 1437-3262 VL - 104 IS - 6 SP - 1667 EP - 1677 PB - Springer CY - New York ER - TY - JOUR A1 - Green-Saxena, A. A1 - Feyzullayev, A. A1 - Hubert, C. R. J. A1 - Kallmeyer, Jens A1 - Krueger, M. A1 - Sauer, P. A1 - Schulz, Hans-Martin A1 - Orphan, V. J. T1 - Active sulfur cycling by diverse mesophilic and thermophilic microorganisms in terrestrial mud volcanoes of Azerbaijan JF - Environmental microbiology N2 - Terrestrial mud volcanoes (TMVs) represent geochemically diverse habitats with varying sulfur sources and yet sulfur cycling in these environments remains largely unexplored. Here we characterized the sulfur-metabolizing microorganisms and activity in four TMVs in Azerbaijan. A combination of geochemical analyses, biological rate measurements and molecular diversity surveys (targeting metabolic genes aprA and dsrA and SSU ribosomal RNA) supported the presence of active sulfur-oxidizing and sulfate-reducing guilds in all four TMVs across a range of physiochemical conditions, with diversity of these guilds being unique to each TMV. The TMVs varied in potential sulfate reduction rates (SRR) by up to four orders of magnitude with highest SRR observed in sediments where in situ sulfate concentrations were highest. Maximum temperatures at which SRR were measured was 60 degrees C in two TMVs. Corresponding with these trends in SRR, members of the potentially thermophilic, spore-forming, Desulfotomaculum were detected in these TMVs by targeted 16S rRNA analysis. Additional sulfate-reducing bacterial lineages included members of the Desulfobacteraceae and Desulfobulbaceae detected by aprA and dsrA analyses and likely contributing to the mesophilic SRR measured. Phylotypes affiliated with sulfide-oxidizing Gamma- and Betaproteobacteria were abundant in aprA libraries from low sulfate TMVs, while the highest sulfate TMV harboured 16S rRNA phylotypes associated with sulfur-oxidizing Epsilonproteobacteria. Altogether, the biogeochemical and microbiological data indicate these unique terrestrial habitats support diverse active sulfur-cycling microorganisms reflecting the in situ geochemical environment. Y1 - 2012 U6 - https://doi.org/10.1111/1462-2920.12015 SN - 1462-2912 VL - 14 IS - 12 SP - 3271 EP - 3286 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Kallmeyer, Jens A1 - Pockalny, Robert A1 - Adhikari, Rishi Ram A1 - Smith, David C. A1 - D'Hondt, Steven T1 - Global distribution of microbial abundance and biomass in subseafloor sediment JF - Proceedings of the National Academy of Sciences of the United States of America N2 - The global geographic distribution of subseafloor sedimentary microbes and the cause(s) of that distribution are largely unexplored. Here, we show that total microbial cell abundance in subseafloor sediment varies between sites by ca. five orders of magnitude. This variation is strongly correlated with mean sedimentation rate and distance from land. Based on these correlations, we estimate global subseafloor sedimentary microbial abundance to be 2.9 center dot 10(29) cells [corresponding to 4.1 petagram (Pg) C and similar to 0.6% of Earth's total living biomass]. This estimate of subseafloor sedimentary microbial abundance is roughly equal to previous estimates of total microbial abundance in seawater and total microbial abundance in soil. It is much lower than previous estimates of subseafloor sedimentary microbial abundance. In consequence, we estimate Earth's total number of microbes and total living biomass to be, respectively, 50-78% and 10-45% lower than previous estimates. KW - deep biosphere KW - cell enumeration KW - global microbial biomass KW - subsurface life Y1 - 2012 U6 - https://doi.org/10.1073/pnas.1203849109 SN - 0027-8424 VL - 109 IS - 40 SP - 16213 EP - 16216 PB - National Acad. of Sciences CY - Washington ER - TY - JOUR A1 - Lappe, Michael A1 - Kallmeyer, Jens T1 - A cell extraction method for oily sediments JF - Frontiers in microbiology N2 - Hydrocarbons can be found in many different habitats and represent an important carbon source for microbes. As fossil fuels, they are also an important economical resource and through natural seepage or accidental release they can be major pollutants. DNA-specific stains and molecular probes bind to hydrocarbons, causing massive background fluorescence, thereby hampering cell enumeration. The cell extraction procedure of Kallmeyer et al. (2008) separates the cells from the sediment matrix. In principle, this technique can also be used to separate cells from oily sediments, but it was not originally optimized for this application. Here we present a modified extraction method in which the hydrocarbons are removed prior to cell extraction. Due to the reduced background fluorescence the microscopic image becomes clearer, making cell identification, and enumeration much easier. Consequently, the resulting cell counts from oily samples treated according to our new protocol are significantly higher than those treated according to Kallmeyer et al. (2008). We tested different amounts of a variety of solvents for their ability to remove hydrocarbons and found that n-hexane and in samples containing more mature oils methanol, delivered the best results. However, as solvents also tend to lyse cells, it was important to find the optimum solvent to sample ratio, at which hydrocarbon extraction is maximized and cell lysis minimized. A volumetric ratio of 1:2-1:5 between a formalin-fixed sediment slurry and solvent delivered highest cell counts. Extraction efficiency was around 30-50% and was checked on both oily samples spiked with known amounts of E. coli cells and oil-free samples amended with fresh and biodegraded oil. The method provided reproducible results on samples containing very different kinds of oils with regard to their degree of biodegradation. For strongly biodegraded oil MeOH turned out to be the most appropriate solvent, whereas for less biodegraded samples n-hexane delivered best results. KW - cell enumeration KW - hydrocarbons KW - cell separation KW - subsurface microbiology Y1 - 2011 U6 - https://doi.org/10.3389/fmicb.2011.00233 SN - 1664-302X VL - 2 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Sauer, Patrick A1 - Glombitza, Clemens A1 - Kallmeyer, Jens T1 - A system for incubations at high gas partial pressure JF - Frontiers in microbiology N2 - High-pressure is a key feature of deep subsurface environments. High partial pressure of dissolved gasses plays an important role in microbial metabolism, because thermodynamic feasibility of many reactions depends on the concentration of reactants. For gases, this is controlled by their partial pressure, which can exceed 1 MPa at in situ conditions. Therefore, high hydrostatic pressure alone is not sufficient to recreate true deep subsurface in situ conditions, but the partial pressure of dissolved gasses has to be controlled as well. We developed an incubation system that allows for incubations at hydrostatic pressure up to 60 MPa, temperatures up to 120 degrees C, and at high gas partial pressure. The composition and partial pressure of gasses can be manipulated during the experiment. To keep costs low, the system is mainly made from off-the-shelf components with only very few custommade parts. A flexible and inert PVDF (polyvinylidene fluoride) incubator sleeve, which is almost impermeable for gases, holds the sample and separates it from the pressure fluid. The flexibility of the incubator sleeve allows for sub-sampling of the medium without loss of pressure. Experiments can be run in both static and flow-through mode. The incubation system described here is usable for versatile purposes, not only the incubation of microorganisms and determination of growth rates, but also for chemical degradation or extraction experiments under high gas saturation, e.g., fluid-gas-rock-interactions in relation to carbon dioxide sequestration. As an application of the system we extracted organic compounds from sub-bituminous coal using H2O as well as a H2O-CO2 mixture at elevated temperature (90 degrees C) and pressure (5 MPa). Subsamples were taken at different time points during the incubation and analyzed by ion chromatography. Furthermore we demonstrated the applicability of the system for studies of microbial activity, using samples from the Isis mud volcano. We could detect an increase in sulfate reduction rate upon the addition of methane to the sample. KW - high-pressure incubation system KW - gas partial pressure KW - sub-sampling KW - carbon dioxide KW - low molecular weight organic acids Y1 - 2012 U6 - https://doi.org/10.3389/fmicb.2012.00025 SN - 1664-302X VL - 3 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Kallmeyer, Jens ED - Laskin, AI ED - Sariaslani, S ED - Gadd, GM T1 - Detection and quantification of microbial cells in subsurface sediments JF - Advances in applied microbiology JF - Advances in Applied Microbiology N2 - Quantification of total cell abundance is one of the most fundamental parameters in the exploration of subsurface life. Despite all recent advances in molecular techniques, this parameter is usually determined by fluorescence microscopy. In order to obtain reliable and reproducible results, it is important not just to focus on the actual cell enumeration but also to consider the entire chain of processing. Starting with the retrieval of the sample, over subsampling and sample processing to the final step of fluorescence microscopy, there are many potential sources of contamination that have to be assessed and, if possible, avoided. Because some degree of sample contamination will always occur, it is necessary to employ some form of contamination control. Different tracers are available, each one with its specific advantages and drawbacks. In many cases, the problems arise not after the sample has arrived in a well-equipped laboratory with highly trained personnel, but much earlier at the drill site or in a field camp. In this review, I discuss the different aspects of cell enumeration in subsurface sediment, evaluating every step in the long process chain. Y1 - 2011 SN - 978-0-12-387048-3 U6 - https://doi.org/10.1016/B978-0-12-387048-3.00003-9 SN - 0065-2164 VL - 76 SP - 79 EP - 103 PB - Elsevier CY - San Diego ER - TY - JOUR A1 - Alawi, Mashal A1 - Schneider, Beate A1 - Kallmeyer, Jens T1 - A procedure for separate recovery of extra- and intracellular DNA from a single marine sediment sample JF - Journal of microbiological methods N2 - Extracellular DNA (eDNA) is a ubiquitous biological compound in aquatic sediment and soil. Previous studies suggested that eDNA plays an important role in biogeochemical element cycling, horizontal gene transfer and stabilization of biofilm structures. Previous methods for eDNA extraction were either not suitable for oligotrophic sediments or only allowed quantification but no genetic analyses. Our procedure is based on cell detachment and eDNA liberation from sediment particles by sequential washing with an alkaline sodium phosphate buffer followed by a separation of cells and eDNA. The separated eDNA is then bound onto silica particles and purified, whereas the intracellular DNA from the separated cells is extracted using a commercial kit. The method provides extra- and intracellular DNA of high purity that is suitable for downstream applications like PCR. Extracellular DNA was extracted from organic-rich shallow sediment of the Baltic Sea, glacially influenced sediment of the Barents Sea and from the oligotrophic South Pacific Gyre. The eDNA concentration in these samples varied from 23 to 626 ng g(-1) wet weight sediment. A number of experiments were performed to verify each processing step. Although extraction efficiency is higher than other published methods, it is not fully quantitative. (C) 2014 Elsevier B.V. All rights reserved. KW - Extracellular DNA KW - eDNA KW - Intracellular DNA KW - South Pacific Gyre KW - Ancient DNA KW - Fossil DNA Y1 - 2014 U6 - https://doi.org/10.1016/j.mimet.2014.06.009 SN - 0167-7012 SN - 1872-8359 VL - 104 SP - 36 EP - 42 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Adhikari, Rishi Ram A1 - Glombitza, Clemens A1 - Nickel, Julia C. A1 - Anderson, Chloe H. A1 - Dunlea, Ann G. A1 - Spivack, Arthur J. A1 - Murray, Richard W. A1 - D’Hondt, Steven A1 - Kallmeyer, Jens T1 - Hydrogen utilization potential in subsurface sediments T2 - Frontiers in microbiology N2 - Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific, and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute a diverse family of enzymes expressed by microorganisms that utilize molecular hydrogen as a metabolic substrate, product, or intermediate. The assay reveals the potential for utilizing molecular hydrogen and allows qualitative detection of microbial activity irrespective of the predominant electron-accepting process. Because the method only requires samples frozen immediately after recovery, the assay can be used for identifying microbial activity in subsurface ecosystems without the need to preserve live material. We measured potential hydrogen oxidation rates in all samples from multiple depths at several sites that collectively span a wide range of environmental conditions and biogeochemical zones. Potential activity normalized to total cell abundance ranges over five orders of magnitude and varies, dependent upon the predominant terminal electron acceptor. Lowest per-cell potential rates characterize the zone of nitrate reduction and highest per-cell potential rates occur in the methanogenic zone. Possible reasons for this relationship to predominant electron acceptor include (i) increasing importance of fermentation in successively deeper biogeochemical zones and (ii) adaptation of H(2)ases to successively higher concentrations of H-2 in successively deeper zones. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 447 KW - hydrogenase KW - tritium assay KW - deep biosphere KW - microbial activity KW - Lake Van KW - Barents Sea KW - Equatorial Pacific KW - Gulf of Mexico Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-407678 ER - TY - JOUR A1 - Adhikari, Rishi Ram A1 - Glombitza, Clemens A1 - Nickel, Julia C. A1 - Anderson, Chloe H. A1 - Dunlea, Ann G. A1 - Spivack, Arthur J. A1 - Murray, Richard W. A1 - Kallmeyer, Jens T1 - Hydrogen Utilization Potential in Subsurface Sediments JF - Frontiers in microbiology N2 - Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific, and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute a diverse family of enzymes expressed by microorganisms that utilize molecular hydrogen as a metabolic substrate, product, or intermediate. The assay reveals the potential for utilizing molecular hydrogen and allows qualitative detection of microbial activity irrespective of the predominant electron-accepting process. Because the method only requires samples frozen immediately after recovery, the assay can be used for identifying microbial activity in subsurface ecosystems without the need to preserve live material. We measured potential hydrogen oxidation rates in all samples from multiple depths at several sites that collectively span a wide range of environmental conditions and biogeochemical zones. Potential activity normalized to total cell abundance ranges over five orders of magnitude and varies, dependent upon the predominant terminal electron acceptor. Lowest per-cell potential rates characterize the zone of nitrate reduction and highest per-cell potential rates occur in the methanogenic zone. Possible reasons for this relationship to predominant electron acceptor include (i) increasing importance of fermentation in successively deeper biogeochemical zones and (ii) adaptation of H(2)ases to successively higher concentrations of H-2 in successively deeper zones. KW - hydrogenase KW - tritium assay KW - deep biosphere KW - microbial activity KW - Lake Van KW - Barents Sea KW - Equatorial Pacific KW - Gulf of Mexico Y1 - 2016 U6 - https://doi.org/10.3389/fmicb.2016.00008 SN - 1664-302X VL - 7 PB - Frontiers Research Foundation CY - Lausanne ER - TY - GEN A1 - Kallmeyer, Jens A1 - Grewe, Sina A1 - Glombitza, Clemens A1 - Kitte, J. Axel T1 - Microbial abundance in lacustrine sediments BT - a case study from Lake Van, Turkey T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - The ICDP "PaleoVan" drilling campaign at Lake Van, Turkey, provided a long (> 100 m) record of lacustrine subsurface sedimentary microbial cell abundance. After the ICDP campaign at Potrok Aike, Argentina, this is only the second time deep lacustrine cell counts have been documented. Two sites were cored and revealed a strikingly similar cell distribution despite differences in organic matter content and microbial activity. Although shifted towards higher values, cell counts from Lake Potrok Aike, Argentina, reveal very similar distribution patterns with depth. The lacustrine cell count data are significantly different from published marine records; the most probable cause is differences in sedimentary organic matter composition with marine sediments containing a higher fraction of labile organic matter. Previous studies showed that microbial activity and abundance increase centimetres to metres around geologic interfaces. The finely laminated Lake Van sediment allowed studying this phenomenon on the microscale. We sampled at the scale of individual laminae, and in some depth intervals, we found large differences in microbial abundance between the different laminae. This small-scale heterogeneity is normally overlooked due to much larger sampling intervals that integrate over several centimetres. However, not all laminated intervals exhibit such large differences in microbial abundance, and some non-laminated horizons show large variability on the millimetre scale as well. The reasons for such contrasting observations remain elusive, but indicate that heterogeneity of microbial abundance in subsurface sediments has not been taken into account sufficiently. These findings have implications not just for microbiological studies but for geochemistry as well, as the large differences in microbial abundance clearly show that there are distinct microhabitats that deviate considerably from the surrounding layers. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 723 KW - subsurface biosphere KW - deep biosphere KW - Lake Van KW - cell counts KW - lacustrine sediment Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-429828 SN - 1866-8372 IS - 723 SP - 1667 EP - 1677 ER - TY - GEN A1 - Vuillemin, Aurèle A1 - Friese, André A1 - Alawi, Mashal A1 - Henny, Cynthia A1 - Nomosatryo, Sulung A1 - Wagner, Dirk A1 - Crowe, Sean A. A1 - Kallmeyer, Jens T1 - Geomicrobiological features of ferruginous sediments from Lake Towuti, Indonesia T2 - Frontiers in microbiology N2 - Lake Towuti is a tectonic basin, surrounded by ultramafic rocks. Lateritic soils form through weathering and deliver abundant iron (oxy)hydroxides but very little sulfate to the lake and its sediment. To characterize the sediment biogeochemistry, we collected cores at three sites with increasing water depth and decreasing bottom water oxygen concentrations. Microbial cell densities were highest at the shallow site a feature we attribute to the availability of labile organic matter (OM) and the higher abundance of electron acceptors due to oxic bottom water conditions. At the two other sites, OM degradation and reduction processes below the oxycline led to partial electron acceptor depletion. Genetic information preserved in the sediment as extracellular DNA (eDNA) provided information on aerobic and anaerobic heterotrophs related to Nitrospirae. Chloroflexi, and Therrnoplasmatales. These taxa apparently played a significant role in the degradation of sinking OM. However, eDNA concentrations rapidly decreased with core depth. Despite very low sulfate concentrations, sulfate-reducing bacteria were present and viable in sediments at all three sites, as confirmed by measurement of potential sulfate reduction rates. Microbial community fingerprinting supported the presence of taxa related to Deltaproteobacteria and Firmicutes with demonstrated capacity for iron and sulfate reduction. Concomitantly, sequences of Ruminococcaceae, Clostridiales, and Methanornicrobiales indicated potential for fermentative hydrogen and methane production. Such first insights into ferruginous sediments showed that microbial populations perform successive metabolisms related to sulfur, iron, and methane. In theory, iron reduction could reoxidize reduced sulfur compounds and desorb OM from iron minerals to allow remineralization to methane. Overall, we found that biogeochemical processes in the sediments can be linked to redox differences in the bottom waters of the three sites, like oxidant concentrations and the supply of labile OM. At the scale of the lacustrine record, our geomicrobiological study should provide a means to link the extant subsurface biosphere to past environments. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 440 KW - bottom waters KW - iron-rich sediment KW - sedimentary microbes KW - extracellular DNA KW - sulfate reduction KW - iron reduction KW - Lake Towuti Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-407312 ER - TY - JOUR A1 - Fischer, Tomáš A1 - Hrubcova, Pavla A1 - Dahm, Torsten A1 - Woith, Heiko A1 - Vylita, Tomáš A1 - Ohrnberger, Matthias A1 - Vlček, Josef A1 - Horalek, Josef A1 - Dedecek, Petr A1 - Zimmer, Martin A1 - Lipus, Martin P. A1 - Pierdominici, Simona A1 - Kallmeyer, Jens A1 - Krüger, Frank A1 - Hannemann, Katrin A1 - Korn, Michael A1 - Kaempf, Horst A1 - Reinsch, Thomas A1 - Klicpera, Jakub A1 - Vollmer, Daniel A1 - Daskalopoulou, Kyriaki T1 - ICDP drilling of the Eger Rift observatory BT - magmatic fluids driving the earthquake swarms and deep biosphere JF - Scientific drilling : reports on deep earth sampling and monitoring N2 - 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 Nový Kostel seismogenic zone, borehole F3 in the Hartoušov mofette field and borehole S4 in the newly discovered Bažina maar near Libá. 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. Y1 - 2022 U6 - https://doi.org/10.5194/sd-31-31-2022 SN - 1816-8957 SN - 1816-3459 VL - 31 SP - 31 EP - 49 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Fischer, Tomas A1 - Hrubcova, Pavla A1 - Dahm, Torsten A1 - Woith, Heiko A1 - Vylita, Tomas A1 - Ohrnberger, Matthias A1 - Vlcek, Josef A1 - Horalek, Josef A1 - Dedecek, Petr A1 - Zimmer, Martin A1 - Lipus, Martin P. A1 - Pierdominici, Simona A1 - Kallmeyer, Jens A1 - Krüger, Frank A1 - Hannemann, Katrin A1 - Korn, Michael A1 - Kämpf, Horst A1 - Reinsch, Thomas A1 - Klicpera, Jakub A1 - Vollmer, Daniel A1 - Daskalopoulou, Kyriaki T1 - ICDP drilling of the Eger Rift observatory BT - magmatic fluids driving the earthquake swarms and deep biosphere JF - Scientific Drilling N2 - 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. Y1 - 2022 U6 - https://doi.org/10.5194/sd-31-31-2022 SN - 1816-8957 SN - 1816-3459 VL - 31 SP - 31 EP - 49 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Nagakura, Toshiki A1 - Schubert, Florian A1 - Wagner, Dirk A1 - Kallmeyer, Jens T1 - Biological sulfate reduction in deep subseafloor sediment of Guaymas Basin JF - Frontiers in microbiology N2 - 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. KW - sulfate reduction KW - subsurface life KW - deep biosphere KW - thermophiles; KW - Guaymas Basin Y1 - 2022 U6 - https://doi.org/10.3389/fmicb.2022.845250 SN - 1664-302X VL - 13 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Nomosatryo, Sulung A1 - Tjallingii, Rik A1 - Henny, Cynthia A1 - Ridwansyah, Iwan A1 - Wagner, Dirk A1 - Tomás, Sara A1 - Kallmeyer, Jens T1 - Surface sediment composition and depositional environments in tropical Lake Sentani, Papua Province, Indonesia JF - Journal of Paleolimnology N2 - Tropical Lake Sentani in the Indonesian Province Papua consists of four separate basins and is surrounded by a catchment with a very diverse geology. We characterized the surface sediment (upper 5 cm) of the lake's four sub-basins based on multivariate statistical analyses (principal component analysis, hierarchical clustering) of major element compositions obtained by X-ray fluorescence scanning. Three types of sediment are identified based on distinct compositional differences between rivers, shallow/proximal and deep/distal lake sediments. The different sediment types are mainly characterized by the correlation of elements associated with redox processes (S, Mn, Fe), carbonates (Ca), and detrital input (Ti, Al, Si, K) derived by river discharge. The relatively coarse-grained river sediments mainly derive form the mafic catchment geology and contribution of the limestone catchment geology is only limited. Correlation of redox sensitive and detrital elements are used to reveal oxidation conditions, and indicate oxic conditions in river samples and reducing conditions for lake sediments. Organic carbon (TOC) generally correlates with redox sensitive elements, although a correlation between TOC and individual elements change strongly between the three sediment types. Pyrite is the quantitatively dominant reduced sulfur mineral, monosulfides only reach appreciable concentrations in samples from rivers draining mafic and ultramafic catchments. Our study shows large spatial heterogeneity within the lake's sub-basins that is mainly caused by catchment geology and topography, river runoff as well as the bathymetry and the depth of the oxycline. We show that knowledge about lateral heterogeneity is crucial for understanding the geochemical and sedimentological variations recorded by these sediments. The highly variable conditions make Lake Sentani a natural laboratory, with its different sub-basins representing different depositional environments under identical tropical climate conditions. KW - Tropical lake KW - Lacustrine sediment KW - XRF analysis KW - Multivariate KW - statistics Y1 - 2022 U6 - https://doi.org/10.1007/s10933-022-00259-4 SN - 0921-2728 SN - 1573-0417 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Nickel, Julia C. A1 - di Primio, Rolando A1 - Mangelsdorf, Kai A1 - Stoddart, Daniel A1 - Kallmeyer, Jens T1 - Characterization of microbial activity in pockmark fields of the SW-Barents Sea JF - Marine geology : international journal of marine geology, geochemistry and geophysics N2 - Multibeam bathymetry revealed the occurrence of numerous craterlike depressions, so-called pockmarks, on the sea floor of the Hammerfest Basin and the Loppa High, south-western Barents Sea. To investigate whether these pockmarks are related to ongoing gas seepage, microbial processes associated with methane metabolism were analyzed using geochemical, biogeochemical and microbiological techniques. Gravity cores were collected along transects crossing individual pockmarks, allowing a direct comparison between different locations inside (assumed activity center), on the rim, and outside of a pockmark (reference sites). Concentrations of hydrocarbons in the sediment, particularly methane, were measured as headspace (free) gas, and in the occluded and adsorbed gas fraction. Down to a depth of 2.6 m below sea floor (mbsf) sulfate reduction rates were quantified by radiotracer incubations. Concentrations of dissolved sulfate in the porewater were determined as well. Neither the sulfate profiles nor the gas measurements show any evidence of microbial activity or active fluid venting. Methane concentrations and sulfate reduction rates were extremely low or even below the detection limit. The results show that the observed sediment structures are most likely paleo-pockmarks, their formation probably occurred during the last deglaciation. KW - pockmark KW - Barents Sea KW - sulfate reduction KW - microbial activity KW - Loppa High Y1 - 2012 U6 - https://doi.org/10.1016/j.margeo.2012.02.002 SN - 0025-3227 VL - 332 IS - 12 SP - 152 EP - 162 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mitzscherling, Julia A1 - Horn, Fabian A1 - Winterfeld, Maria A1 - Mahler, Linda A1 - Kallmeyer, Jens A1 - Overduin, Pier Paul A1 - Schirrmeister, Lutz A1 - Winkel, Matthias A1 - Grigoriev, Mikhail N. A1 - Wagner, Dirk A1 - Liebner, Susanne T1 - Microbial community composition and abundance after millennia of submarine permafrost warming JF - Biogeosciences N2 - 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. Y1 - 2019 U6 - https://doi.org/10.5194/bg-16-3941-2019 SN - 1726-4170 SN - 1726-4189 VL - 16 IS - 19 SP - 3941 EP - 3958 PB - Copernicus CY - Göttingen ER -