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  • 1
    Call number: AWI G3-08-0003
    Type of Medium: Monograph available for loan
    Pages: 246 S. : graph. Darst., Ill.
    Language: English
    Note: Potsdam, Univ., Habil.-Schr., 2007
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  • 2
    Call number: AWI Bio-20-93990
    Description / Table of Contents: Assumed comparable environmental conditions of early Mars and early Earth in 3.7 Ga ago – at a time when first fossil records of life on Earth could be found – suggest the possibility of life emerging on both planets in parallel. As conditions changed, the hypothetical life on Mars either became extinct or was able to adapt and might still exist in biological niches. The controversial discussed detection of methane on Mars led to the assumption, that it must have a recent origin – either abiotic through active volcanism or chemical processes, or through biogenic production. Spatial and seasonal variations in the detected methane concentrations and correlations between the presence of water vapor and geological features such as subsurface hydrogen, which are occurring together with locally increased detected concentrations of methane, gave fuel to the hypothesis of a possible biological source of the methane on Mars. Therefore the phylogenetically old methanogenic archaea, which have evolved under early Earth conditions, are often used as model-organisms in astrobiological studies to investigate the potential of life to exist in possible extraterrestrial habitats on our neighboring planet. In this thesis methanogenic archaea originating from two extreme environments on Earth were investigated to test their ability to be active under simulated Mars analog conditions. These extreme environments – the Siberian permafrost-affected soil and the chemoautotrophically based terrestrial ecosystem of Movile cave, Romania – are regarded as analogs for possible Martian (subsurface) habitats. Two novel species of methanogenic archaea isolated from these environments were described within the frame of this thesis. It could be shown that concentrations up to 1 wt% of Mars regolith analogs added to the growth media had a positive influence on the methane production rates of the tested methanogenic archaea, whereas higher concentrations resulted in decreasing rates. Nevertheless it was possible for the organisms to metabolize when incubated on water-saturated soil matrixes made of Mars regolith analogs without any additional nutrients. Long-term desiccation resistance of more than 400 days was proven with reincubation and indirect counting of viable cells through a combined treatment with propidium monoazide (to inactivate DNA of destroyed cells) and quantitative PCR. Phyllosilicate rich regolith analogs seem to be the best soil mixtures for the tested methanogenic archaea to be active under Mars analog conditions. Furthermore, in a simulation chamber experiment the activity of the permafrost methanogen strain Methanosarcina soligelidi SMA-21 under Mars subsurface analog conditions could be proven. Through real-time wavelength modulation spectroscopy measurements the increase in the methane concentration at temperatures down to -5 °C could be detected. The results presented in this thesis contribute to the understanding of the activity potential of methanogenic archaea under Mars analog conditions and therefore provide insights to the possible habitability of present-day Mars (near) subsurface environments. Thus, it contributes also to the data interpretation of future life detection missions on that planet. For example the ExoMars mission of the European Space Agency (ESA) and Roscosmos which is planned to be launched in 2018 and is aiming to drill in the Martian subsurface
    Type of Medium: Dissertations
    Pages: VI, 108 Blätter , Illustrationen
    Language: English
    Note: Dissertation, Universität Potsdam, 2015 , Table of contents Preface Table of contents Summary Zusammenfassung 1. Introduction 1.1. Environmental conditions on past and present Mars 1.2. Detection of methane on Mars 1.3. Methanogenic archaea 1.4. Description of study sites 1.5. Aims and approaches 1.6. Overview of the publications 2. Publication I: Methanosarcina soligelidi sp. nov., a desiccationandfreeze-thaw-resistant methanogenic archaeon from a Siberianpermafrost-affected soil 3. Publication II: Methanobacterium movilense sp. nov.,ahydrogenotrophic, secondary-alcohol-utilizing methanogen fromthe anoxic sediment of a subsurface lake 4. Publication III: Influence of Martian Regolith Analogs on the activityand growth of methanogenic archaea,with special regard to long-term desiccation 5. Publication IV: Laser spectroscopic real time measurements ofmethanogenic activity under simulated Martian subsurface conditions 6. Synthesis and Conclusion 6.1. Synthesis 6.2. Conclusion and future perspectives 7. References 8. Acknowledgments
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  • 3
    Call number: ZSP-168-716
    In: Berichte zur Polar- und Meeresforschung, 716
    Type of Medium: Series available for loan
    Pages: 211 Seiten , Illustrationen
    ISSN: 1866-3192
    Series Statement: Berichte zur Polar- und Meeresforschung 716
    Language: English
    Note: Contents Characterization of soil organic matter of Arctic and Antarctic by 13- C NMR and electron spin resonance spectroscopy / Evgeny Abakumov Development of phosphorus forms in soil chronosequence of the Nordenskioldbreen glacier (Svalbard) / Adel Allaberdina, Václav Tejnecký Vertical snow structures from in-situ and remote sensing measurements / Stefanie Arndt, Nicolas Stoll, Stephan Paul, Christian Haas Phenology of Calanus glacialis – comparison between Arctic and Atlantic domains and its implications for reproductive success of little auks / Kaja Balazy, Emilia Trudnowska, Katarzyna Blachowiak-Samolyk Response of southern tundra ecosystem components on aerial pollution from gas pre-treatment centers in West Siberia / Pavel A. Barsukov Soil-ecological excursions to permafrost-affected areas in West Siberia for European scientists and students / Pavel A. Barsukov, S. Platonova, S. Gizhitskaya, E. Smolentseva, N. Lashchinskiy, A. Babenko, I. Lyubechanskiy, O. Saprykin, O.Rusalimova Christian Siewert Freezing and hungry? Hydrocarbon degrading microbial communities in Barents Sea sediments around Svalbard / Bartholomäus Sven, Nontje Straaten, Daniela Zoch, Martin Krüger Biological soil crust algae in the polar regions – biodiversity, genetic diversity and ecosystem resilience under global change scenarios / Burkhard Becker, Burkhard Büdel and Ulf Karsten UDASH - Unified Database for Arctic and Subarctic Hydrography / Axel Behrendt, Hiroshi Sumata, Benjamin Rabe, Torsten Kanzow and Ursula Schauer Compound-specific radiocarbon constraints on Antarctic sediment chronologies / Sonja Berg, Sandra Jivcov, Janet Rethemeyer Environmental conditions in terrestrial East Antarctica during the last glacial - new evidence from mumiyo deposits / Sonja Berg, Martin Melles, Wolf-Dieter Hermichen, Janet Rethemeyer, Gerhard Kuhn Collection-based diatom research: collection imaging to biogeography and microevolution in the Southern Ocean / Bánk Beszteri, Stefan Pinkernell, Michael Kloster, Ute Postel, Gerhard Kauer, Uwe John, Klaus Valentin, Gernot Glöckner In vivo observations of OWA induced pH changes in the brain of polar cod Boreogadus saida / Christian Bock, Felizitas C. Wermter, Bastian Maus, Hans-O. Pörtner, Wolfgang Dreher A journey into the Triassic polar forests of Antarctica / Benjamin Bomfleur Long-term time-series of Arctic BrO derived from UV-VIS satellite remote sensing / lias Bougoudis, Anne-Marlene Blechschmidt, Andreas Richter, Sora Seo, John P. Burrows The effect of climate change on the carbon balance in microalgae / Deborah Bozzato, Torsten Jakob, Christian Wilhelm Species composition and abundance of the shallow water fish community of Kongsfjorden, Svalbard / Markus Brand, Philipp Fischer Decadal changes in a breeding population of southern giant petrels on King George Island, Antarctic, in response to human activities / Christina Braun, Jan Esefeld, Hans-Ulrich Peter Geodetic GNSS measurements to investigate the recent crustal deformation at the Antarctic Peninsula and in the Amundsen Sea Embayment, West Antarctica / Peter Busch, Mirko Scheinert, Christoph Knöfel, Lutz Eberlein, Martin Horwath, Ludwig Schröder, Andreas Groh Parameterization of snow BRDF measurements in Antarctica / T. Carlsen, G. Birnbaum, A. Ehrlich, M. Schäfer, and M. Wendisch Airborne and in situ ground-based measurements of surface albedo, bidirectional reflectivity, and snow properties on the Antarctic plateau / T. Carlsen, M. Belke Brea, G. Birnbaum, A. Ehrlich, J. Freitag, G. Heygster, L. Istomina, S. Kipfstuhl, A. Orsi, M. Schäfer, and M. Wendisch Retreats of ice sheet and ice shelf driven by warm water incursions in the Ross Sea since the Last Glacial Maximum / Zhihua Chen, Mengshan Ju, Shulan Ge, Zheng Tang, Yuanhui Huang, Renjie Zhao, Ralf Tiedemann, Lester Lembke-Jene Influence of breeze circulation on local wind climatology in Svalbard fjords / Małgorzata Cisek, Przemysław Makuch, Tomasz Petelski, Jacek Piskozub Life strategies on photobiology and metabolite profile of genetic indentical photobionts of two different lichen species / Nadine Determeyer-Wiedmann, Sieglinde Ott Land-Ocean Interactions in the late glacial Bering Sea / B. Diekmann, R. Wang, H. Kühn, R. Gersonde, R. Tiedemann, G. Kuhn Does environmental change affect polar microbial communities? / Daniel R. Dietrich Rapid glacial isostatic uplift in Patagonia: Interplay of enhanced ice mass loss and slab window tectonics / R. Dietrich, A. Richter, E. Ivins, H. Lange, L. Mendoza, L. Schröder, J.L. Hormaechea, G. Casassa, E. Marderwald, M. Fritsche, R. Perdomo, M. Horwath Phylogenomics of the longitarsal Colossendeidae: the evolution of a diverse Antarctic sea spider radiation / Lars Dietz, Jana S. Dömel, Christoph Mayer, Florian Leese Revealing the evolutionary history of Southern Ocean sea spiders using genome-wide SNP data / Jana S. Dömel, Till-Hendrik Macher, Lars Dietz, Christoph Mayer, Roland R. Melzer and Florian Leese Geothermal heat flux derived from airborne magnetic grids and measured temperature gradients in the Amundsen Sea sector of West Antarctica / Ricarda Dziadek, Karsten Gohl, Fausto Ferraccioli, Norbert Kaul, Cornelia Spiegel Sea spray aerosol fluxes in the area of the Spitsbergen Shelf and the Greenland Sea / K. Dziembor, T. Petelski, P. Markuszewski, T. Zieliński, P. Makuch, I. Wróbel More than two decades of geodetic GNSS measurements in Antarctica, Greenland and Patagonia – a technology review / Lutz Eberlein, Mirko Scheinert, Peter Busch, Christoph Knöfel, Andreas Richter Analysing the flow velocity of major outlet glaciers in North Greenland using Landsat data / Benjamin Ebermann, Ralf Rosenau, Mirko Scheinert, Martin Horwath Partitioning growing season net ecosystem exchange of CO2 into photosynthesis, autotrophic and heterotrophic respiration in the Siberian tundra / Tim Eckhardt, Christian Knoblauch, Lars Kutzbach, Gillian Simpson, Eva-Maria Pfeiffer Meteorological collaboration in the Arctic / Johanna Ekman Meteorological aspects of S.A. Andrée’s attempt to reach the North Pole by balloon in 1897 / Dieter Etling Geodetic mass balance on South Georgia glaciers / David Farias-Barahona, Christian Sommer, Thorsten Seehaus, Philipp Malz, Gino Casassa, Matthias H. Braun Frozen-Ground Cartoons: An international collaboration between artists and permafrost scientists / Michael Fritz, Frédéric Bouchard, Bethany Deshpande, Julie Malenfant-Lepage, Alexandre Nieuwendam, Michel Paquette, Ashley Rudy, Matthias Siewert, Audrey Veillette, Stefanie Weege, Jon Harbor, Otto Habeck, Ylva Sjöberg The Akademii Nauk ice core and solar activity / Diedrich Fritzsche, Luisa von Albedyll, Silke Merchel, Thomas Opel, Georg Rugel, Andreas Scharf Walther Bruns, Gründer der „Aeroarctic“ – ein vergessener Pionier der Deutschen Polarforschung / Diedrich Fritzsche Warming and reduction of precipitations affect the microbiome of recently deglaciated soils in the Swiss Alps / Aline Frossard, Johanna Donhauser, Pascal Niklaus, Thomas Rime, Beat Frey The ice-free topography of Svalbard / Johannes J. Fürst, Francisco Navarro, Fabien Gillet-Chaulet, Geir Moholdt, Xavier Fettweis, Charlotte Lang, Thorsten Seehaus, Matthias H. Braun, Douglas I. Benn, Toby J. Benham, Julian A. Dowdeswell, Mariusz Grabiec, Jack Kohler, Katrin Lindbäck, Rickard Pettersson, Heidi Sevestre Scientific Drilling in Antarctica? Coming to a new drilling proposal / Christoph Gaedicke, Gerhard Kuhn, Olaf Eisen, Andreas Läufer, Emma Smith, Nikola Koglin, Boris Biskaborn, Dieter Franke, Ralf Tiedemann German permanent research facilities in Antarctica - a 40 years record / Hartwig Gernandt Pre-glacial and glacial shelf evolution from seismic and seabed drill records of the Amundsen Sea, West Antarctica / Karsten Gohl, Gabriele Uenzelmann-Neben, Robert Larter, Johann Klages, Claus-Dieter Hillenbrand, Torsten Bickert, Steve Bohaty, Ulrich Salzmann, Thomas Frederichs, Catalina Gebhardt, Katharina Hochmuth and Expedition PS104 Science Party The Turnove
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  • 4
    Monograph available for loan
    Monograph available for loan
    Berlin [u.a.] : Walter de Gruyter
    Call number: 20-2/M 14.0104
    Description / Table of Contents: Over the last two decades, exploration of the deep subsurface biosphere has developed into a major research area. New findings constantly challenge our concepts of global biogeochemical cycles and the ultimate limits to life.In order to explain our observations from deep subsurface ecosystems it is necessary to develop truly interdisciplinary approaches, ranging from microbiology and geochemistry to physics and modeling.This book aims to bring together a wide variety of topics, covering the broad range of issues that are associated with deep biosphere exploration. Not only does the book present case studies of selected projects, but also treats questions arising from our current knowledge. Despite nearly two decades of research, there are still many boundaries to exploration caused by technical limitations and one section of the book is devoted to these technical challenges and the latest developments in this field. This volume will be of high interest to biologists, chemists and earth scientists all working on the deep biosphere.
    Type of Medium: Monograph available for loan
    Pages: xvii, 325 S. : farb. Ill+ graph. Darst.
    ISBN: 9783110300093
    Series Statement: Life in extreme environments 1
    detail.hit.classification_display:
    D.8.
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  • 5
    Call number: ZS-090(466) ; ZSP-168-466
    In: Berichte zur Polar- und Meeresforschung
    Type of Medium: Series available for loan
    Pages: iv, 341 S.
    ISSN: 1618-3193
    Series Statement: Berichte zur Polar- und Meeresforschung 466
    detail.hit.classification_display:
    D.3.
    Language: English
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  • 6
    Series available for loan
    Series available for loan
    Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung
    Associated volumes
    Call number: ZSP-168-539 ; ZS-090(539)
    In: Berichte zur Polar- und Meeresforschung
    Type of Medium: Series available for loan
    Pages: 123 S. : Ill., graph. Darst., Kt.
    ISSN: 1618-3193
    Series Statement: Berichte zur Polar- und Meeresforschung 539
    Language: English
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  • 7
    Call number: AWI G3-18-91503
    In: Hamburger bodenkundliche Arbeiten, Band 40
    Type of Medium: Series available for loan
    Pages: XVIII, 153 S , Ill., graph. Darst , 21 cm
    ISSN: 0724-6382
    Series Statement: Hamburger bodenkundliche Arbeiten 40
    Language: German
    Note: Zugl.: Hamburg, Univ., FB Geowiss., Diss., 1998 , Inhaltsverzeichnis: I Zusammenfassung. - II Summary. - III Abbildungsverzeichnis. - IV Tabellenverzeichnis. - V Abkürzungsverzeichnis. - VI Glossar. - 1 Einleitung und Fragestellung. - 2 Grundlagen. - 2.1 Methan in der Natur. - 2.2 Methan als klimarelevantes Spurengas. - 2.3 Der Methankreislauf. - 2.4 Methanogene Bakterien. - 2.5 Anaerober Abbau organischer Substanz. - 2.6 Isotopieeffekte beim mikrobiellen anaeroben Abbau organischer Substanz. - 2.7 Bedeutung terrestrischer Ökosysteme für die Methanfreisetzung. - 3 Charakterisierung der Untersuchungsgebiete. - 3.1 Asseler Sand (Assel, Norddeutschland). - 3.1.1 Lage und naturräumliche Gliederung. - 3.1.2 Landschaftsgenese. - 3.1.3 Klima. - 3.1.4 Hydrologie. - 3.1.5 Vegetation und Nutzung. - 3.1.6 Böden des Untersuchungsgebietes. - 3.2 Tai-Hu-Tiefland (Suzhou, Ostchina). - 3.2.1 Lage. - 3.2.2 Landschaftsgenese. - 3.2.3 Klima. - 3.2.4 Vegetation und Nutzung. - 3.2.5 Böden des Untersuchungsgebietes. - 4 Material und Methoden. - 4.1 Bodenprofilaufnahme und Probenentnahme. - 4.2 Behandlung und Aufarbeitung des Probenmaterials. - 4.3 Bodenphysikalische Analysen. - 4.3.1 Bestimmung der Porengrößenverteilung. - 4.3.2 Bestimmung der Korngrößenverteilung. - 4.4 Bodenchemische Analysen. - 4.4.1 Kohlenstoff- und Stickstoff-Analytik. - 4.4.2 δ13C-Bestimmung. - 4.4.3 pH-Wert- und Redoxpotential-Messung. - 4.5 Bestimmung von Methanbildungsraten. - 4.5.1 Aktuelle Methanbildungsaktivität. - 4.5.2 Potentielle Methanbildungsaktivität. - 4.5.3 Temperaturoptimum der Methanbildung. - 4.5.4 Methanbildungsaktivität in Gegenwart von Sauerstoff. - 4.5.5 Methanbildungsaktivität in Abhängigkeit vom Wassergehalt. - 4.5.6 Gasanalytik (CH4, O2). - 4.6 Mikrobiologische Untersuchungen. - 4.6.1 Nährmedien. - 4.6.2 Zellzahlbestimmung. - 4.6.2.1 MPN-Methode. - 4.6.2.2 Koch'sches Plattengußverfahren. - 4.6.3 Isolierung von methanogenen Bakterien. - 4.6.3.1 Anreicherungskultur. - 4.6.3.2 Agar-Verdünnungsreihe. - 4.6.3.3 Reinheitstest. - 4.6.3.4 Kulturführung. - 4.6.4 Charakterisierung der Isolate. - 4.6.4.1 Transmissionselektronenmikroskopie. - 4.6.4.2 Substratspektrum. - 4.6.4.3 Temperaturoptimum. - 4.6.4.4 Salz- und pH-Optimum. - 4.6.4.5 16S-rRNA-Sequenzierung. - 4.7 Fraktionierung der organischen Bodensubstanz. - 4.7.1 DOC-Extraktion. - 4.7.2 Dichtefraktionierung. - 4.8 Statistische Analysen. - 5 Ergebnisse. - 5.1 Bodenmikrobiologische Standortcharakterisierung. - 5.1.1 Marschboden (Asseler Sand). - 5.1.2 Reisboden (Suzhou). - 5.2 Temperaturcharakteristika der methanogenen Flora. - 5.2.1 Temperaturoptimum. - 5.2.2 Zellzahlen methanogener Bakterien in Abhängigkeit von Temperatur und Substrat. - 5.2.3 Einfluß verschiedener Substrate auf die Methanbildung. - 5.3 Isolierung und Charakterisierung von methanogenen Bakterien. - 5.3.1 Grundlagen. - 5.3.2 Morphologische Merkmale. - 5.3.3 Physiologische Merkmale. - 5.3.4 Phylogenetische Auswertung der 16S-rRNA-Sequenzen methanogener Bakterien. - 5.4 Methanbildung in Gegenwart von Sauerstoff. - 5.4.1 Hemmung der Methanoxidation durch Acetylen. - 5.4.2 Einfluß der Begleitflora. - 5.4.3 Einfluß der Bodenart. - 5.4.4 Methanbildung bei definierten Wassergehalten. - 5.5 Charakterisierung der organischen Bodensubstanz in Hinblick auf die CH4-Bildung. - 5.5.1 Marschboden (Asseler Sand). - 5.5.1.1 Kohlenstoff- und Stickstoff-Parameter. - 5.5.1.2 Isotopenanalytische Untersuchung der organischen Bodensubstanz. - 5.5.1.3 Charakterisierung der organischen Substanz mittels Dichtefraktionierung. - 5.5.2 Reisboden (Suzhou). - 5.5.2.1 Kohlenstoff- und Stickstoff-Parameter. - 5.5.2.2 Isotopenanalytische Untersuchungen der organischen Bodensubstanz. - 5.5.2.3 Charakterisierung der organischen Substanz mittels Dichtefraktionierung. - 5.5.2.4 Methanbildungspotentiale der Dichtefraktionen. - 6 Diskussion. - 6.1 Einfluß der Temperatur auf die Methanbildung. - 6.2 Einfluß von Sauerstoff auf die Aktivität methanogener Bakterien. - 6.3 Bedeutung der organischen Bodensubstanz für die Methanogenese. - 6.4 Wechselwirkungen der untersuchten Faktoren in hydromorphen Böden und ihre Bedeutung in Hinblick auf globale Klimaveränderungen. - 7 Literaturverzeichnis. - 8 Anhang. - Danksagung.
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  • 8
    Call number: AWI Bio-20-93529
    Description / Table of Contents: The Arctic is considered as a focal region in the ongoing climate change debate. The currently observed and predicted climate warming is particularly pronounced in the high northern latitudes. Rising temperatures in the Arctic cause progressive deepening and duration of permafrost thawing during the arctic summer, creating an ‘active layer’ with high bioavailability of nutrients and labile carbon for microbial consumption. The microbial mineralization of permafrost carbon creates large amounts of greenhouse gases, including carbon dioxide and methane, which can be released to the atmosphere, creating a positive feedback to global warming. However, to date, the microbial communities that drive the overall carbon cycle and specifically methane production in the Arctic are poorly constrained. To assess how these microbial communities will respond to the predicted climate changes, such as an increase in atmospheric and soil temperatures causing increased bioavailability of organic carbon, it is necessary to investigate the current status …
    Type of Medium: Dissertations
    Pages: 146 Blätter , Illustrationen
    Language: English
    Note: Table of content Abstract Zusammenfassung 1. Introduction 1.1. Motivation 1.2. Scientific Background 1.2.1. Permafrost in arctic environments 1.2.2. Carbon storage and emission in arctic environments 1.2.3. Methane cycling in arctic environments 1.3. Study Sites 1.3.1. Lena-Delta, Siberia 1.3.2. El’gygytgyn Crater Lake, Chukotka 1.4. Objectives and approach 1.5. Thesis organization 1.6. Summary of the included manuscripts and contribution of the co-authors 1.6.1. Response of methanogenic archaea to Late Pleistocene and Holocene climate changes in the Siberian Arctic 1.6.2. Response of microbial communities to landscape and climatic changes in a terrestrial permafrost sequence of the El’gygytgyn crater, Far East Russian Arctic 1.6.3. Glacial-interglacial microbial community dynamics in Middle Pleistocene sediments in the Lake El’gygytgyn, Far East Russian Arctic 2. Response of methanogenic archaea to Late Pleistocene and Holocene climate changes in the Siberian Arctic 2.1. Abstract 2.2. Introduction 2.3. Materials and Methods 2.3.1. Study site 2.3.2. Permafrost drilling and sample preparation 2.3.3. Sediment properties 2.3.4. Potential methane production rates 2.3.5. Lipid biomarker analysis 2.3.6. Detection of archaeol and isoprenoid GDGTs 2.3.7. Detection of PLFAs and PLELs 2.3.8. DNA extraction and polymerase chain reaction (PCR) amplification 2.3.9. Phylogenetic analysis 2.4. Results and Discussion 2.4.1. Methane profile of the Kurungnakh permafrost sequence 2.4.2. Signals of living microbial communities in the Kurungnakh permafrost sequence 2.4.3. Reconstruction of past microbial communities in the Kurungnakh permafrost sequence 2.4.4. Climate impact on the distribution of microbial communities in the Kurungnakh permafrost sequence 2.4.5. Climatic impact on the composition of methanogenic communities in the Kurungnakh permafrost sequence 2.5. Conclusion 2.6. Acknowledgement 3. Response of microbial communities to landscape and climatic changes in a terrestrial permafrost sequence of the El’gygytgyn crater, Far East Russian Arctic 3.1. Abstract 3.2. Introduction 3.3. Materials and Methods 3.3.1.Study site 3.3.2. Drilling and sample material 3.3.3. Sediment properties 3.3.4. Lipid biomarker analysis 3.3.5. Detection of glycerol dialkyl glycerol tetraethers (GDGTs) and archaeol 3.3.6. Detection of phospholipid fatty acids (PLFA) 3.3.7. Deoxyribonucleic acid (DNA) extraction and amplification 3.3.8. Quantitative PCR analysis of archaeal and bacterial small sub unit (SSU) rRNA genes 3.3.9. Phylogenetic analysis 3.4. Results 3.4.1. TOC-contents 3.4.2. Distribution of glycerol dialkyl glycerol tetraethers (GDGTs) and archaeol 3.4.3. Distribution of phospholipid fatty acids (PLFA) 3.4.4. Composition of archaeol and isoprenoid GDGTs 3.4.5. Quantification of bacterial and archaeal genes 3.4.6. Analysis of methanogenic community fingerprints 3.5. Discussion 3.5.1. Microbial communities in subaquatic deposits 3.5.2. Microbial communities in subaerial deposits 3.5.3. Microbial succession in the Holocene sequence of Lake El’gygytgyn permafrost 3.6.Conclusion 3.7. Acknowledgements 4. Glacial-interglacial microbial community dynamics in Middle Pleistocene sediments in the Lake El’gygytgyn, Far East Russian Arctic 4.1. Abstract 4.2. Introduction 4.3. Materials and Methods 4.3.1. Study site 4.3.2. Drilling and sample preparation 4.3.3. Sediment properties 4.3.4. Lipid biomarker analyses 4.3.5. Deoxyribonucleic acid (DNA) extraction and quantitative polymerase chain reaction (qPCR) 4.3.6. PCR amplification of methanogenic SSU rRNA genes 4.4. Results 4.4.1. Sedimentary TOC and biogenic silica concentration 4.4.2. Quantification of bacterial and archaeal genes 4.4.3. Quantification and composition of lipid biomarkers 4.4.4. Potential methane production 4.4.5. Methanogenic community composition 4.5. Discussion 4.6. Acknowledgements 5. Synthesis 5.1. The reaction of microbial communities to past climatic change in the Arctic 5.2.The response of microbial communities to carbon composition and availability 5.3. Implications from this study for future research 6. Data collection 6.1. Manuscript I: Response of methanogenic archaea to Late Pleistocene and Holocene climate changes in the Siberian Arctic 6.1.1. Sediment properties 6.1.2. Isoprenoid glycerol dialkyl glycerol tetraethers and archaeol 6.1.3. Branched glycerol dialkyl glycerol tetraethers 6.1.4. Phospholipid ester and ether lipids (summary) 6.2. Manuscript II: Response of microbial communities to landscape and climatic changes in a terrestrial permafrost sequence of the El’gygytgyn crater, Far East Russian Arctic 6.2.1. Sediment properties and gene quantifications 6.2.2. Phospholipid fatty acids composition 6.2.3. Isoprenoid glycerol dialkyl glycerol tetraethers and archaeol 6.2.4. Branched glycerol dialkyl glycerol tetraethers 6.3. Manuscript III: Glacial-interglacial microbial community dynamics in Middle Pleistocene sediments in the Lake El’gygytgyn, Far East Russian Arctic 6.3.1. Sediment properties and gene quantifications 6.3.2. Isoprenoid glycerol dialkyl glycerol tetraethers and archaeol 6.3.3. Branched glycerol dialkylglycerol tetraethers 7. References 8. Final thoughts and acknowledgements 9. Curriculum vitae 10.Erklärung
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  • 9
    Publication Date: 2014-04-14
    Description: Permafrost-affected soils are among the most obvious ecosystems in which current microbial controls on organic matter decomposition are changing as a result of global warming. Warmer conditions in polygonal tundra will lead to a deepening of the seasonal active layer, provoking changes in microbial processes and possibly resulting in exacerbated carbon degradation under increasing anoxic conditions. To identify current microbial assemblages in carbon rich, water saturated permafrost environments, four polygonal tundra sites were investigated on Herschel Island and the Yukon Coast, Western Canadian Arctic. Ion Torrent sequencing of bacterial and archaeal 16S rRNA amplicons revealed the presence of all major microbial soil groups and indicated a local, vertical heterogeneity of the polygonal tundra soil community with increasing depth. Microbial diversity was found to be highest in the surface layers, decreasing towards the permafrost table. Quantitative PCR analysis of functional genes involved in carbon and nitrogen-cycling revealed a high functional potential in the surface layers, decreasing with increasing active layer depth. We observed that soil properties driving microbial diversity and functional potential varied in each study site. These results highlight the small-scale heterogeneity of geomorphologically comparable sites, greatly restricting generalizations about the fate of permafrost-affected environments in a warming Arctic.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 10
    Publication Date: 2014-05-23
    Description: Microbial permafrost communities play an important role in carbon cycling and greenhouse gas fluxes. Despite the importance of these processes, there is a lack of knowledge about how environmental and climatic changes affect the abundance and composition of microorganisms. Here, we investigated the changing distribution of permafrost microorganisms in response to climate and lake-level changes. The permafrost core was drilled at the near shore of Lake El'gygytgyn, Far East Russian Arctic, and a combined microbiological and lipid biomarker approach was applied. The lower part of the permafrost core, deposited under subaquatic conditions, contains only small amounts of microbial signals; total organic carbon (TOC) content is sparse. After exposure of the site to subaerial conditions during the Allerød, the abundance of Bacteria and Archaea started to increase and the lake-level change is especially evidenced by the relative proportion of archaeal biomarkers. This increase is supported by rising bacterial and archaeal 16S ribosomal ribonucleic acid (rRNA) gene copy numbers and significant amounts of TOC during the late Allerød. After a small decrease during the colder Younger Dryas, the TOC content and the microbial signals strongly increase during the Holocene, presumably stimulated by pedogenesis. The occurrence of intact phospholipids indicates the presence of living microorganisms in these deposits. Our data suggest that methane formation is mainly expected for the subaerial interval, especially the Holocene where methanogens were identified by fingerprinting. This study emphasises the role of the uppermost permafrost deposits as a hotspot of carbon cycling in arctic environments, especially in the light of expected future global warming.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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