@misc{DietzeMangelsdorfAndreevetal.2020, author = {Dietze, Elisabeth and Mangelsdorf, Kai and Andreev, Andrei and Karger, Cornelia and Schreuder, Laura T. and Hopmans, Ellen C. and Rach, Oliver and Sachse, Dirk and Wennrich, Volker and Herzschuh, Ulrike}, title = {Relationships between low-temperature fires, climate and vegetation during three late glacials and interglacials of the last 430 kyr in northeastern Siberia reconstructed from monosaccharide anhydrides in Lake El'gygytgyn sediments}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {2}, issn = {1866-8372}, doi = {10.25932/publishup-51684}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-516843}, pages = {22}, year = {2020}, abstract = {Landscapes in high northern latitudes are assumed to be highly sensitive to future global change, but the rates and long-term trajectories of changes are rather uncertain. In the boreal zone, fires are an important factor in climate-vegetation interactions and biogeochemical cycles. Fire regimes are characterized by small, frequent, low-intensity fires within summergreen boreal forests dominated by larch, whereas evergreen boreal forests dominated by spruce and pine burn large areas less frequently but at higher intensities. Here, we explore the potential of the monosaccharide anhydrides (MA) levoglucosan, mannosan and galactosan to serve as proxies of low-intensity biomass burning in glacial-to-interglacial lake sediments from the high northern latitudes. We use sediments from Lake El'gygytgyn (cores PG 1351 and ICDP 5011-1), located in the far north-east of Russia, and study glacial and interglacial samples of the last 430 kyr (marine isotope stages 5e, 6, 7e, 8, 11c and 12) that had different climate and biome configurations. Combined with pollen and non-pollen palynomorph records from the same samples, we assess how far the modern relationships between fire, climate and vegetation persisted during the past, on orbital to centennial timescales. We find that MAs attached to particulates were well-preserved in up to 430 kyr old sediments with higher influxes from low-intensity biomass burning in interglacials compared to glacials. MA influxes significantly increase when summergreen boreal forest spreads closer to the lake, whereas they decrease when tundra-steppe environments and, especially, Sphagnum peatlands spread. This suggests that low-temperature fires are a typical characteristic of Siberian larch forests also on long timescales. The results also suggest that low-intensity fires would be reduced by vegetation shifts towards very dry environments due to reduced biomass availability, as well as by shifts towards peatlands, which limits fuel dryness. In addition, we observed very low MA ratios, which we interpret as high contributions of galactosan and mannosan from biomass sources other than those currently monitored, such as the moss-lichen mats in the understorey of the summergreen boreal forest. Overall, sedimentary MAs can provide a powerful proxy for fire regime reconstructions and extend our knowledge of long-term natural fire-climate-vegetation feedbacks in the high northern latitudes.}, language = {en} } @article{DietzeMangelsdorfAndreevetal.2020, author = {Dietze, Elisabeth and Mangelsdorf, Kai and Andreev, Andrei and Karger, Cornelia and Schreuder, Laura T. and Hopmans, Ellen C. and Rach, Oliver and Sachse, Dirk and Wennrich, Volker and Herzschuh, Ulrike}, title = {Relationships between low-temperature fires, climate and vegetation during three late glacials and interglacials of the last 430 kyr in northeastern Siberia reconstructed from monosaccharide anhydrides in Lake El'gygytgyn sediments}, series = {Climate of the Past}, volume = {16}, journal = {Climate of the Past}, number = {2}, publisher = {Copernicus Publications}, address = {G{\"o}ttingen}, issn = {1814-9332}, doi = {10.5194/cp-16-799-2020}, pages = {788 -- 818}, year = {2020}, abstract = {Landscapes in high northern latitudes are assumed to be highly sensitive to future global change, but the rates and long-term trajectories of changes are rather uncertain. In the boreal zone, fires are an important factor in climate-vegetation interactions and biogeochemical cycles. Fire regimes are characterized by small, frequent, low-intensity fires within summergreen boreal forests dominated by larch, whereas evergreen boreal forests dominated by spruce and pine burn large areas less frequently but at higher intensities. Here, we explore the potential of the monosaccharide anhydrides (MA) levoglucosan, mannosan and galactosan to serve as proxies of low-intensity biomass burning in glacial-to-interglacial lake sediments from the high northern latitudes. We use sediments from Lake El'gygytgyn (cores PG 1351 and ICDP 5011-1), located in the far north-east of Russia, and study glacial and interglacial samples of the last 430 kyr (marine isotope stages 5e, 6, 7e, 8, 11c and 12) that had different climate and biome configurations. Combined with pollen and non-pollen palynomorph records from the same samples, we assess how far the modern relationships between fire, climate and vegetation persisted during the past, on orbital to centennial timescales. We find that MAs attached to particulates were well-preserved in up to 430 kyr old sediments with higher influxes from low-intensity biomass burning in interglacials compared to glacials. MA influxes significantly increase when summergreen boreal forest spreads closer to the lake, whereas they decrease when tundra-steppe environments and, especially, Sphagnum peatlands spread. This suggests that low-temperature fires are a typical characteristic of Siberian larch forests also on long timescales. The results also suggest that low-intensity fires would be reduced by vegetation shifts towards very dry environments due to reduced biomass availability, as well as by shifts towards peatlands, which limits fuel dryness. In addition, we observed very low MA ratios, which we interpret as high contributions of galactosan and mannosan from biomass sources other than those currently monitored, such as the moss-lichen mats in the understorey of the summergreen boreal forest. Overall, sedimentary MAs can provide a powerful proxy for fire regime reconstructions and extend our knowledge of long-term natural fire-climate-vegetation feedbacks in the high northern latitudes.}, language = {en} } @misc{GenderjahnAlawiMangelsdorfetal.2018, author = {Genderjahn, Steffi and Alawi, Mashal and Mangelsdorf, Kai and Horn, Fabian and Wagner, Dirk}, title = {Desiccation- and saline-tolerant bacteria and archaea in Kalahari pan sediments}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {993}, issn = {1866-8372}, doi = {10.25932/publishup-45915}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-459154}, pages = {17}, 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{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{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{GenderjahnLewinHornetal.2021, author = {Genderjahn, Steffi and Lewin, Simon and Horn, Fabian and Schleicher, Anja M. and Mangelsdorf, Kai and Wagner, Dirk}, title = {Living lithic and sublithic bacterial communities in Namibian drylands}, series = {Microorganisms : open access journal}, volume = {9}, journal = {Microorganisms : open access journal}, number = {2}, publisher = {MDPI}, address = {Basel}, issn = {2076-2607}, doi = {10.3390/microorganisms9020235}, pages = {20}, year = {2021}, abstract = {Dryland xeric conditions exert a deterministic effect on microbial communities, forcing life into refuge niches. Deposited rocks can form a lithic niche for microorganisms in desert regions. Mineral weathering is a key process in soil formation and the importance of microbial-driven mineral weathering for nutrient extraction is increasingly accepted. Advances in geobiology provide insight into the interactions between microorganisms and minerals that play an important role in weathering processes. In this study, we present the examination of the microbial diversity in dryland rocks from the Tsauchab River banks in Namibia. We paired culture-independent 16S rRNA gene amplicon sequencing with culture-dependent (isolation of bacteria) techniques to assess the community structure and diversity patterns. Bacteria isolated from dryland rocks are typical of xeric environments and are described as being involved in rock weathering processes. For the first time, we extracted extra- and intracellular DNA from rocks to enhance our understanding of potentially rock-weathering microorganisms. We compared the microbial community structure in different rock types (limestone, quartz-rich sandstone and quartz-rich shale) with adjacent soils below the rocks. Our results indicate differences in the living lithic and sublithic microbial communities.}, language = {en} } @article{GlombitzaMangelsdorfHorsfield2011, author = {Glombitza, Clemens and Mangelsdorf, Kai and Horsfield, Brian}, title = {Structural insights from boron tribromide ether cleavage into lignites and low maturity coals from the New Zealand Coal Band}, series = {Organic geochemistry : the international journal for rapid publication of current research in organic geochemistry and biochemistry}, volume = {42}, journal = {Organic geochemistry : the international journal for rapid publication of current research in organic geochemistry and biochemistry}, number = {3}, publisher = {Elsevier}, address = {Oxford}, issn = {0146-6380}, doi = {10.1016/j.orggeochem.2010.12.005}, pages = {228 -- 236}, year = {2011}, abstract = {Ether functionalities form an important cross-linking structure within the macromolecular organic matrix of lignites and coals. To obtain a deeper insight into the complex internal structure of such macromolecules and the maturation related changes of the ether compounds within the network structure, boron tribromide (BBr3) ether cleavage was applied to a series of lignite and coal samples of different maturity (R-0 0.27-0.80\%) obtained from coal mines and natural outcrops from the North and South Island of New Zealand. Terminal ether-bound alcohols rapidly decrease during diagenesis and occur only in low amounts during the catagenetic stage. Comparison between ester- and ether-bound terminal alcohols indicates a parallel decreasing trend during the diagenetic stage, suggesting that the stability differences between both linkages are not large enough to be observed in maturation processes over geological time scales:Polyether compounds were detected with chain length up to five carbon atoms. After a small decrease during the diagenetic phase these compounds occur in relatively high concentrations, even in the main catagenetic stage. This suggests that these linkage structures represent important cross-linking substructures within the macromolecular matrix of lignites and coals being sterically protected within the macromolecular network during the maturation process. Additional cross-linking substructures were (poly)ether aromatics, esters and ketones.}, language = {en} } @article{HaugkJongejansMangelsdorfetal.2022, author = {Haugk, Charlotte and Jongejans, Loeka L. and Mangelsdorf, Kai and Fuchs, Matthias and Ogneva, Olga and Palmtag, Juri and Mollenhauer, Gesine and Mann, Paul J. and Overduin, P. Paul and Grosse, Guido and Sanders, Tina and Tuerena, Robyn E. and Schirrmeister, Lutz and Wetterich, Sebastian and Kizyakov, Alexander and Karger, Cornelia and Strauss, Jens}, title = {Organic matter characteristics of a rapidly eroding permafrost cliff in NE Siberia (Lena Delta, Laptev Sea region)}, series = {Biogeosciences}, volume = {19}, journal = {Biogeosciences}, number = {7}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1726-4170}, doi = {10.5194/bg-19-2079-2022}, pages = {2079 -- 2094}, year = {2022}, abstract = {Organic carbon (OC) stored in Arctic permafrost represents one of Earth's largest and most vulnerable terrestrial carbon pools. Amplified climate warming across the Arctic results in widespread permafrost thaw. Permafrost deposits exposed at river cliffs and coasts are particularly susceptible to thawing processes. Accelerating erosion of terrestrial permafrost along shorelines leads to increased transfer of organic matter (OM) to nearshore waters. However, the amount of terrestrial permafrost carbon and nitrogen as well as the OM quality in these deposits is still poorly quantified. We define the OM quality as the intrinsic potential for further transformation, decomposition and mineralisation. Here, we characterise the sources and the quality of OM supplied to the Lena River at a rapidly eroding permafrost river shoreline cliff in the eastern part of the delta (Sobo-Sise Island). Our multi-proxy approach captures bulk elemental, molecu- lar geochemical and carbon isotopic analyses of Late Pleistocene Yedoma permafrost and Holocene cover deposits, discontinuously spanning the last similar to 52 kyr. We showed that the ancient permafrost exposed in the Sobo-Sise cliff has a high organic carbon content (mean of about 5 wt \%). The oldest sediments stem from Marine Isotope Stage (MIS) 3 interstadial deposits (dated to 52 to 28 cal ka BP) and are overlaid by last glacial MIS 2 (dated to 28 to 15 cal ka BP) and Holocene MIS 1 (dated to 7-0 cal ka BP) deposits. The relatively high average chain length (ACL) index of n-alkanes along the cliff profile indicates a predominant contribution of vascular plants to the OM composition. The elevated ratio of isoand anteiso-branched fatty acids (FAs) relative to mid- and long-chain (C >= 20) n-FAs in the interstadial MIS 3 and the interglacial MIS 1 deposits suggests stronger microbial activity and consequently higher input of bacterial biomass during these climatically warmer periods. The overall high carbon preference index (CPI) and higher plant fatty acid (HPFA) values as well as high C/N ratios point to a good quality of the preserved OM and thus to a high potential of the OM for decomposition upon thaw. A decrease in HPFA values downwards along the profile probably indicates stronger OM decomposition in the oldest (MIS 3) deposits of the cliff. The characterisation of OM from eroding permafrost leads to a better assessment of the greenhouse gas potential of the OC released into river and nearshore waters in the future.}, language = {en} } @misc{JongejansStraussLenzetal.2018, author = {Jongejans, Loeka Laura and Strauss, Jens and Lenz, Josefine and Peterse, Francien and Mangelsdorf, Kai and Fuchs, Matthias and Grosse, Guido}, title = {Organic matter characteristics in yedoma and thermokarst deposits on Baldwin Peninsula, west Alaska}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {20}, issn = {1866-8372}, doi = {10.25932/publishup-44625}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-446250}, pages = {6033 -- 6048}, year = {2018}, abstract = {As Arctic warming continues and permafrost thaws, more soil and sedimentary organic matter (OM) will be decomposed in northern high latitudes. Still, uncertainties remain in the quality of the OM and the size of the organic carbon (OC) pools stored in different deposit types of permafrost landscapes. This study presents OM data from deep permafrost and lake deposits on the Baldwin Peninsula which is located in the southern portion of the continuous permafrost zone in west Alaska. Sediment samples from yedoma and drained thermokarst lake basin (DTLB) deposits as well as thermokarst lake sediments were analyzed for cryostratigraphical and biogeochemical parameters and their lipid biomarker composition to identify the below-ground OC pool size and OM quality of ice-rich permafrost on the Baldwin Peninsula. We provide the first detailed characterization of yedoma deposits on Baldwin Peninsula. We show that three-quarters of soil OC in the frozen deposits of the study region (total of 68 Mt) is stored in DTLB deposits (52 Mt) and one-quarter in the frozen yedoma deposits (16 Mt). The lake sediments contain a relatively small OC pool (4 Mt), but have the highest volumetric OC content (93 kgm(-3)) compared to the DTLB (35 kgm(-3)) and yedoma deposits (8 kgm(-3)), largely due to differences in the ground ice content. The biomarker analysis indicates that the OM in both yedoma and DTLB deposits is mainly of terrestrial origin. Nevertheless, the relatively high carbon preference index of plant leaf waxes in combination with a lack of a degradation trend with depth in the yedoma deposits indi-cates that OM stored in yedoma is less degraded than that stored in DTLB deposits. This suggests that OM in yedoma has a higher potential for decomposition upon thaw, despite the relatively small size of this pool. These findings show that the use of lipid biomarker analysis is valuable in the assessment of the potential future greenhouse gas emissions from thawing permafrost, especially because this area, close to the discontinuous permafrost boundary, is projected to thaw substantially within the 21st century.}, language = {en} } @article{JongejansStraussLenzetal.2018, author = {Jongejans, Loeka Laura and Strauss, Jens and Lenz, Josefine and Peterse, Francien and Mangelsdorf, Kai and Fuchs, Matthias and Grosse, Guido}, title = {Organic matter characteristics in yedoma and thermokarst deposits on Baldwin Peninsula, west Alaska}, series = {Biogeosciences}, volume = {15}, journal = {Biogeosciences}, number = {20}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1726-4170}, doi = {10.5194/bg-15-6033-2018}, pages = {6033 -- 6048}, year = {2018}, abstract = {As Arctic warming continues and permafrost thaws, more soil and sedimentary organic matter (OM) will be decomposed in northern high latitudes. Still, uncertainties remain in the quality of the OM and the size of the organic carbon (OC) pools stored in different deposit types of permafrost landscapes. This study presents OM data from deep permafrost and lake deposits on the Baldwin Peninsula which is located in the southern portion of the continuous permafrost zone in west Alaska. Sediment samples from yedoma and drained thermokarst lake basin (DTLB) deposits as well as thermokarst lake sediments were analyzed for cryostratigraphical and biogeochemical parameters and their lipid biomarker composition to identify the below-ground OC pool size and OM quality of ice-rich permafrost on the Baldwin Peninsula. We provide the first detailed characterization of yedoma deposits on Baldwin Peninsula. We show that three-quarters of soil OC in the frozen deposits of the study region (total of 68 Mt) is stored in DTLB deposits (52 Mt) and one-quarter in the frozen yedoma deposits (16 Mt). The lake sediments contain a relatively small OC pool (4 Mt), but have the highest volumetric OC content (93 kgm(-3)) compared to the DTLB (35 kgm(-3)) and yedoma deposits (8 kgm(-3)), largely due to differences in the ground ice content. The biomarker analysis indicates that the OM in both yedoma and DTLB deposits is mainly of terrestrial origin. Nevertheless, the relatively high carbon preference index of plant leaf waxes in combination with a lack of a degradation trend with depth in the yedoma deposits indi-cates that OM stored in yedoma is less degraded than that stored in DTLB deposits. This suggests that OM in yedoma has a higher potential for decomposition upon thaw, despite the relatively small size of this pool. These findings show that the use of lipid biomarker analysis is valuable in the assessment of the potential future greenhouse gas emissions from thawing permafrost, especially because this area, close to the discontinuous permafrost boundary, is projected to thaw substantially within the 21st century.}, language = {en} }