@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{BernhardMoskwaSchmidtetal.2018,
  author    = {Bernhard, Nadine and Moskwa, Lisa-Marie and Schmidt, Karsten and Oeser, Ralf Andreas and Aburto, Felipe and Bader, Maaike Y. and Baumann, Karen and von Blanckenburg, Friedhelm and Boy, Jens and van den Brink, Liesbeth and Brucker, Emanuel and Buedel, Burkhard and Canessa, Rafaella and Dippold, Michaela A. and Ehlers, Todd and Fuentes, Juan P. and Godoy, Roberto and Jung, Patrick and Karsten, Ulf and Koester, Moritz and Kuzyakov, Yakov and Leinweber, Peter and Neidhardt, Harald and Matus, Francisco and Mueller, Carsten W. and Oelmann, Yvonne and Oses, Romulo and Osses, Pablo and Paulino, Leandro and Samolov, Elena and Schaller, Mirjam and Schmid, Manuel and Spielvogel, Sandra and Spohn, Marie and Stock, Svenja and Stroncik, Nicole and Tielboerger, Katja and Uebernickel, Kirstin and Scholten, Thomas and Seguel, Oscar and Wagner, Dirk and K{\"u}hn, Peter},
  title     = {Pedogenic and microbial interrelations to regional climate and local topography},
  series = {Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution},
  volume    = {170},
  journal   = {Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0341-8162},
  doi       = {10.1016/j.catena.2018.06.018},
  pages     = {335 -- 355},
  year      = {2018},
  abstract  = {The effects of climate and topography on soil physico-chemical and microbial parameters were studied along an extensive latitudinal climate gradient in the Coastal Cordillera of Chile (26 degrees-38 degrees S). The study sites encompass arid (Pan de Azucar), semiarid (Santa Gracia), mediterranean (La Campana) and humid (Nahuelbuta) climates and vegetation, ranging from arid desert, dominated by biological soil crusts (biocrusts), semiarid shrubland and mediterranean sclerophyllous forest, where biocrusts are present but do have a seasonal pattern to temperate-mixed forest, where biocrusts only occur as an early pioneering development stage after disturbance. All soils originate from granitic parent materials and show very strong differences in pedogenesis intensity and soil depth. Most of the investigated physical, chemical and microbiological soil properties showed distinct trends along the climate gradient. Further, abrupt changes between the arid northernmost study site and the other semi-arid to humid sites can be shown, which indicate non-linearity and thresholds along the climate gradient. Clay and total organic carbon contents (TOC) as well as Ah horizons and solum depths increased from arid to humid climates, whereas bulk density (BD), pH values and base saturation (BS) decreased. These properties demonstrate the accumulation of organic matter, clay formation and element leaching as key-pedogenic processes with increasing humidity. However, the soils in the northern arid climate do not follow this overall latitudinal trend, because texture and BD are largely controlled by aeolian input of dust and sea salts spray followed by the formation of secondary evaporate minerals. Total soil DNA concentrations and TOC increased from arid to humid sites, while areal coverage by biocrusts exhibited an opposite trend. Relative bacterial and archaeal abundances were lower in the arid site, but for the other sites the local variability exceeds the variability along the climate gradient. Differences in soil properties between topographic positions were most pronounced at the study sites with the mediterranean and humid climate, whereas microbial abundances were independent on topography across all study sites. In general, the regional climate is the strongest controlling factor for pedogenesis and microbial parameters in soils developed from the same parent material. Topographic position along individual slopes of limited length augmented this effect only under humid conditions, where water erosion likely relocated particles and elements downward. The change from alkaline to neutral soil pH between the arid and the semi-arid site coincided with qualitative differences in soil formation as well as microbial habitats. This also reflects non-linear relationships of pedogenic and microbial processes in soils depending on climate with a sharp threshold between arid and semi-arid conditions. Therefore, the soils on the transition between arid and semi-arid conditions are especially sensitive and may be well used as indicators of long and medium-term climate changes. Concluding, the unique latitudinal precipitation gradient in the Coastal Cordillera of Chile is predestined to investigate the effects of the main soil forming factor - climate - on pedogenic processes.},
  language  = {en}
}
@article{WojcikDonhauserFreyetal.2018,
  author    = {Wojcik, Robin and Donhauser, Johanna and Frey, Beat W. and Holm, Stine and Holland, Alexandra and Anesio, Alexandre M. and Pearce, David A. and Malard, Lucie and Wagner, Dirk and Benning, Liane G.},
  title     = {Linkages between geochemistry and microbiology in a proglacial terrain in the High Arctic},
  series = {Annals of glaciology},
  volume    = {59},
  journal   = {Annals of glaciology},
  number    = {77},
  publisher = {Cambridge Univ. Press},
  address   = {Cambridge},
  issn      = {0260-3055},
  doi       = {10.1017/aog.2019.1},
  pages     = {95 -- 110},
  year      = {2018},
  abstract  = {Proglacial environments are ideal for studying the development of soils through the changes of rocks exposed by glacier retreat to weathering and microbial processes. Carbon (C) and nitrogen (N) contents as well as soil pH and soil elemental compositions are thought to be dominant factors structuring the bacterial, archaeal and fungal communities in the early stages of soil ecosystem formation. However, the functional linkages between C and N contents, soil composition and microbial community structures remain poorly understood. Here, we describe a multivariate analysis of geochemical properties and associated microbial community structures between a moraine and a glaciofluvial outwash in the proglacial area of a High Arctic glacier (Longyearbreen, Svalbard). Our results reveal distinct differences in developmental stages and heterogeneity between the moraine and the glaciofluvial outwash. We observed significant relationships between C and N contents, delta C-13(org) and delta N-15 isotopic ratios, weathering and microbial abundance and community structures. We suggest that the observed differences in microbial and geochemical parameters between the moraine and the glaciofluvial outwash are primarily a result of geomorphological variations of the proglacial terrain.},
  language  = {en}
}
@article{MasyaginaEvgrafovaBugaenkoetal.2018,
  author    = {Masyagina, Oxana. V. and Evgrafova, S. Yu and Bugaenko, T. N. and Kholodilova, V. V. and Krivobokov, L. and Korets, M. A. and Wagner, Dirk},
  title     = {Permafrost landslides promote soil CO2 emission and hinder C accumulation},
  series = {The science of the total environment : an international journal for scientific research into the environment and its relationship with man},
  volume    = {657},
  journal   = {The science of the total environment : an international journal for scientific research into the environment and its relationship with man},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0048-9697},
  doi       = {10.1016/j.scitotenv.2018.11.468},
  pages     = {351 -- 364},
  year      = {2018},
  abstract  = {Landslides arc common in high-latitude forest ecosystems that have developed on permafrost. The most vulnerable areas in the permafrost territories of Siberia occur on the south-facing slopes of northern rivers, where they arc observed on about 20\% of the total area of river slopes. Landslide disturbances will likely increase with climate change especially due to increasing summer-autumn precipitation. These processes are the most destructive natural disturbance agent and lead to the complete removal of pre-slide forest ecosystems (vegetation cover and soil). To evaluate postsliding ecosystem succession, we undertook integrated ecological research at landslides of different age classes along the Nizhnyaya Tunguska River and the Kochechum River (Tura, Krasnoyarsk region, Russia). Just after the event (at the one-year-old site), we registered a drop in soil respiration, a threefold lower microbial respiration rate, and a fourfold smaller mineral soil carbon and nitrogen stock at bare soil (melkozem) plots at the middle location of the site as compared with the non affected control site. The recovery of disturbed areas began with the re-establishment of plant cover and the following accumulation of an organic soil layer. During the 35-year succession (L1972), the accumulated layer (0 layer)at the oldest site contained similar C- and N stocks to those found at the control sites. However, the mineral soil C- and N stocks and the microbial biomass even of the oldest landslide area- did not reach the value of these parameters in control plots. Later, the soil respiration level and the eco-physiological status of soil microbiota also recovered due to these changes. This study demonstrates that the recovery after landslides in permafrost forests takes several decades. In addition, the degradation of permafrost due to landslides clearly hinders the accumulation of soil organic matter in the mineral soil. (C) 2018 Elsevier B.v. All rights reserved.},
  language  = {en}
}
@article{GenderjahnAlawiMangelsdorfetal.2018,
  author    = {Genderjahn, Steffi and Alawi, Mashal and Mangelsdorf, Kai and Horn, Fabian and Wagner, Dirk},
  title     = {Desiccation- and saline-solerant bacteria and archaea in kalahari an sediments},
  series = {Frontiers in microbiology},
  volume    = {9},
  journal   = {Frontiers in microbiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-302X},
  doi       = {10.3389/fmicb.2018.02082},
  pages     = {15},
  year      = {2018},
  abstract  = {More than 41\% of the Earth's land area is covered by permanent or seasonally arid dryland ecosystems. Global development and human activity have led to an increase in aridity, resulting in ecosystem degradation and desertification around the world. The objective of the present work was to investigate and compare the microbial community structure and geochemical characteristics of two geographically distinct saline pan sediments in the Kalahari Desert of southern Africa. Our data suggest that these microbial communities have been shaped by geochemical drivers, including water content, salinity, and the supply of organic matter. Using Illumina 16S rRNA gene sequencing, this study provides new insights into the diversity of bacteria and archaea in semi-arid, saline, and low-carbon environments. Many of the observed taxa are halophilic and adapted to water-limiting conditions. The analysis reveals a high relative abundance of halophilic archaea (primarily Halobacteria), and the bacterial diversity is marked by an abundance of Gemmatimonadetes and spore-forming Firmicutes. In the deeper, anoxic layers, candidate division MSBL1, and acetogenic bacteria (Acetothermia) are abundant. Together, the taxonomic information and geochemical data suggest that acetogenesis could be a prevalent form of metabolism in the deep layers of a saline pan.},
  language  = {en}
}
@article{LiuKaempfBussertetal.2018,
  author    = {Liu, Qi and K{\"a}mpf, Horst and Bussert, Robert and Krauze, Patryk and Horn, Fabian and Nickschick, Tobias and Plessen, Birgit and Wagner, Dirk and Alawi, Mashal},
  title     = {Influence of CO2 degassing on the microbial community in a dry mofette field in Hartoušov, Czech Republic (Western Eger Rift)},
  series = {Frontiers in Microbiology},
  volume    = {9},
  journal   = {Frontiers in Microbiology},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {1664-302X},
  doi       = {10.3389/fmicb.2018.02787},
  pages     = {17},
  year      = {2018},
  abstract  = {The Cheb Basin (CZ) is a shallow Neogene intracontinental basin filled with fluvial and lacustrine sediments that is located in the western part of the Eger Rift. The basin is situated in a seismically active area and is characterized by diffuse degassing of mantle-derived CO2 in mofette fields. The Hartousov mofette field shows a daily CO2 flux of 23-97 tons of CO2 released over an area of 0.35 km(2) and a soil gas concentration of up to 100\% CO2. The present study aims to explore the geo-bio interactions provoked by the influence of elevated CO2 concentrations on the geochemistry and microbial community of soils and sediments. To sample the strata, two 3-m cores were recovered. One core stems from the center of the degassing structure, whereas the other core was taken 8 m from the ENE and served as an undisturbed reference site. The sites were compared regarding their geochemical features, microbial abundances, and microbial community structures. The mofette site is characterized by a low pH and high TOC/sulfate contents. Striking differences in the microbial community highlight the substantial impact of elevated CO2 concentrations and their associated side effects on microbial processes. The abundance of microbes did not show a typical decrease with depth, indicating that the uprising CO2-rich fluid provides sufficient substrate for chemolithoautotrophic anaerobic microorganisms. Illumine MiSeq sequencing of the 16S rRNA genes and multivariate statistics reveals that the pH strongly influences microbial composition and explains around 38.7\% of the variance at the mofette site and 22.4\% of the variance between the mofette site and the undisturbed reference site. Accordingly, acidophilic microorganisms (e.g., OTUs assigned to Acidobacteriaceae and Acidithiobacillus) displayed a much higher relative abundance at the mofette site than at the reference site. The microbial community at the mofette site is characterized by a high relative abundance of methanogens and taxa involved in sulfur cycling. The present study provides intriguing insights into microbial life and geo-bio interactions in an active seismic region dominated by emanating mantle-derived CO2-rich fluids, and thereby builds the basis for further studies, e.g., focusing on the functional repertoire of the communities. However, it remains open if the observed patterns can be generalized for different time-points or sites.},
  language  = {en}
}
@article{OeserStroncikMoskwaetal.2018,
  author    = {Oeser, Ralf Andreas and Stroncik, Nicole and Moskwa, Lisa-Marie and Bernhard, Nadine and Schaller, Mirjam and Canessa, Rafaella and van den Brink, Liesbeth and K{\"o}ster, Moritz and Brucker, Emanuel and Stock, Svenja and Pablo Fuentes, Juan and Godoy, Roberto and Javier Matus, Francisco and Oses Pedraza, Romulo and Osses McIntyre, Pablo and Paulino, Leandro and Seguel, Oscar and Bader, Maaike Y. and Boy, Jens and Dippold, Michaela A. and Ehlers, Todd and K{\"u}hn, Peter and Kuzyakov, Yakov and Leinweber, Peter and Scholten, Thomas and Spielvogel, Sandra and Spohn, Marie and Ubernickel, Kirstin and Tielb{\"o}rger, Katja and Wagner, Dirk and von Blanckenburg, Friedhelm},
  title     = {Chemistry and microbiology of the Critical Zone along a steep climate and vegetation gradient in the Chilean Coastal Cordillera},
  series = {Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution},
  volume    = {170},
  journal   = {Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0341-8162},
  doi       = {10.1016/j.catena.2018.06.002},
  pages     = {183 -- 203},
  year      = {2018},
  abstract  = {From north to south, denudation rates from cosmogenic nuclides are similar to 10 t km(-2) yr(-1) at the arid Pan de Aziicar site, similar to 20 t km(2) yr(-1) at the semi-arid site of Santa Gracia, -60 t km(-2) yr(-1) at the Mediterranean climate site of La Campana, and similar to 30 t km(-2) yr(-1) at the humid site of Nahuelbuta. A and B horizons increase in thickness and elemental depletion or enrichment increases from north (similar to 26 degrees S) to south (similar to 38 degrees S) in these horizons. Differences in the degree of chemical weathering, quantified by the chemical depletion fraction (CDF), are significant only between the arid and sparsely vegetated site and the other three sites. Differences in the CDF between the sites, and elemental depletion within the sites are sometimes smaller than the variations induced by the bedrock heterogeneity. Microbial abundances (bacteria and archaea) in saprolite substantially increase from the arid to the semi-arid sites. With this study, we provide a comprehensive dataset characterizing the Critical Zone geochemistry in the Chilean Coastal Cordillera. This dataset confirms climatic controls on weathering and denudation rates and provides prerequisites to quantify the role of biota in future studies.},
  language  = {en}
}
@article{GenderjahnAlawiWagneretal.2018,
  author    = {Genderjahn, Steffi and Alawi, Mashal and Wagner, Dirk and Schueller, I. and Wanke, A. and Mangelsdorf, Kai},
  title     = {Microbial community responses to modern environmental and Past Climatic Conditions in Omongwa Pan, Western Kalahari},
  series = {Journal of geophysical research : Biogeosciences},
  volume    = {123},
  journal   = {Journal of geophysical research : Biogeosciences},
  number    = {4},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {2169-8953},
  doi       = {10.1002/2017JG004098},
  pages     = {1333 -- 1351},
  year      = {2018},
  abstract  = {Due to a lack of well-preserved terrestrial climate archives, paleoclimate studies are sparse in southwestern Africa. Because there are no perennial lacustrine systems in this region, this study relies on a saline pan as an archive for climate information in the western Kalahari (Namibia). Molecular biological and biogeochemical analyses were combined to examine the response of indigenous microbial communities to modern and past climate-induced environmental conditions. The 16S rRNA gene high-throughput sequencing was applied to sediment samples from Omongwa pan to characterize the modern microbial diversity. Highest diversity of microorganisms, dominated by the extreme halophilic archaeon Halobacteria and by the bacterial phylum Gemmatimonadetes, was detected in the near-surface sediments of Omongwa pan. In deeper sections abundance and diversity significantly decreases and Bacillus, known to form spores, become dominant. Lipid biomarkers for living and past microbial life were analyzed to track the influence of climate variation on the abundance of microbial communities from the Last Glacial Maximum to Holocene time. Since water is an inevitable requirement for microbial life, in this dry region the abundance of past microbial biomarkers was evaluated to conclude on periods of increased paleoprecipitation in the past. The data point to a period of increased humidity in the western Kalahari during the Last Glacial to Holocene transition indicating a southward shift of the Intertropical Convergence Zone during this period. Comparison with results from a southwestern Kalahari pan suggests complex displacements of the regional atmospheric systems since the Last Glacial Maximum.},
  language  = {en}
}
@article{SchulzeMakuchWagnerKounavesetal.2018,
  author    = {Schulze-Makuch, Dirk and Wagner, Dirk and Kounaves, Samuel P. and Mangelsdorf, Kai and Devine, Kevin G. and de Vera, Jean-Pierre and Schmitt-Kopplin, Philippe and Grossart, Hans-Peter and Parro, Victor and Kaupenjohann, Martin and Galy, Albert and Schneider, Beate and Airo, Alessandro and Froesler, Jan and Davila, Alfonso F. and Arens, Felix L. and Caceres, Luis and Cornejo, Francisco Solis and Carrizo, Daniel and Dartnell, Lewis and DiRuggiero, Jocelyne and Flury, Markus and Ganzert, Lars and Gessner, Mark O. and Grathwohl, Peter and Guan, Lisa and Heinz, Jacob and Hess, Matthias and Keppler, Frank and Maus, Deborah and McKay, Christopher P. and Meckenstock, Rainer U. and Montgomery, Wren and Oberlin, Elizabeth A. and Probst, Alexander J. and Saenz, Johan S. and Sattler, Tobias and Schirmack, Janosch and Sephton, Mark A. and Schloter, Michael and Uhl, Jenny and Valenzuela, Bernardita and Vestergaard, Gisle and Woermer, Lars and Zamorano, Pedro},
  title     = {Transitory microbial habitat in the hyperarid Atacama Desert},
  series = {Proceedings of the National Academy of Sciences of the United States of America},
  volume    = {115},
  journal   = {Proceedings of the National Academy of Sciences of the United States of America},
  number    = {11},
  publisher = {National Acad. of Sciences},
  address   = {Washington},
  issn      = {0027-8424},
  doi       = {10.1073/pnas.1714341115},
  pages     = {2670 -- 2675},
  year      = {2018},
  language  = {en}
}