TY - JOUR A1 - Monhonval, Arthur A1 - Strauss, Jens A1 - Mauclet, Elisabeth A1 - Hirst, Catherine A1 - Bemelmans, Nathan A1 - Grosse, Guido A1 - Schirrmeister, Lutz A1 - Fuchs, Matthias A1 - Opfergelt, Sophie T1 - Iron redistribution upon thermokarst processes in the Yedoma domain JF - Frontiers in Earth Science N2 - Ice-rich permafrost has been subject to abrupt thaw and thermokarst formation in the past and is vulnerable to current global warming. The ice-rich permafrost domain includes Yedoma sediments that have never thawed since deposition during the late Pleistocene and Alas sediments that were formed by previous thermokarst processes during the Lateglacial and Holocene warming. Permafrost thaw unlocks organic carbon (OC) and minerals from these deposits and exposes OC to mineralization. A portion of the OC can be associated with iron (Fe), a redox-sensitive element acting as a trap for OC. Post-depositional thaw processes may have induced changes in redox conditions in these deposits and thereby affected Fe distribution and interactions between OC and Fe, with knock-on effects on the role that Fe plays in mediating present day OC mineralization. To test this hypothesis, we measured Fe concentrations and proportion of Fe oxides and Fe complexed with OC in unthawed Yedoma and previously thawed Alas deposits. Total Fe concentrations were determined on 1,292 sediment samples from the Yedoma domain using portable X-ray fluorescence; these concentrations were corrected for trueness using a calibration based on a subset of 144 samples measured by inductively coupled plasma optical emission spectrometry after alkaline fusion (R (2) = 0.95). The total Fe concentration is stable with depth in Yedoma deposits, but we observe a depletion or accumulation of total Fe in Alas deposits, which experienced previous thaw and/or flooding events. Selective Fe extractions targeting reactive forms of Fe on unthawed and previously thawed deposits highlight that about 25% of the total Fe is present as reactive species, either as crystalline or amorphous oxides, or complexed with OC, with no significant difference in proportions of reactive Fe between Yedoma and Alas deposits. These results suggest that redox driven processes during past thermokarst formation impact the present-day distribution of total Fe, and thereby the total amount of reactive Fe in Alas versus Yedoma deposits. This study highlights that ongoing thermokarst lake formation and drainage dynamics in the Arctic influences reactive Fe distribution and thereby interactions between Fe and OC, OC mineralization rates, and greenhouse gas emissions. KW - permafrost KW - thaw KW - redox processes KW - carbon stabilization KW - arctic KW - subarctic Y1 - 2021 U6 - https://doi.org/10.3389/feart.2021.703339 SN - 2296-6463 VL - 9 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Morgenstern, Anne A1 - Overduin, Pier Paul A1 - Günther, Frank A1 - Stettner, Samuel A1 - Ramage, Justine A1 - Schirrmeister, Lutz A1 - Grigoriev, Mikhail N. A1 - Grosse, Guido T1 - Thermo-erosional valleys in Siberian ice-rich permafrost JF - Permafrost and Periglacial Processes N2 - Thermal erosion is a major mechanism of permafrost degradation, resulting in characteristic landforms. We inventory thermo-erosional valleys in ice-rich coastal lowlands adjacent to the Siberian Laptev Sea based on remote sensing, Geographic Information System (GIS), and field investigations for a first regional assessment of their spatial distribution and characteristics. Three study areas with similar geological (Yedoma Ice Complex) but diverse geomorphological conditions vary in valley areal extent, incision depth, and branching geometry. The most extensive valley networks are incised deeply (up to 35 m) into the broad inclined lowland around Mamontov Klyk. The flat, low-lying plain forming the Buor Khaya Peninsula is more degraded by thermokarst and characterized by long valleys of lower depth with short tributaries. Small, isolated Yedoma Ice Complex remnants in the Lena River Delta predominantly exhibit shorter but deep valleys. Based on these hydrographical network and topography assessments, we discuss geomorphological and hydrological connections to erosion processes. Relative catchment size along with regional slope interact with other Holocene relief-forming processes such as thermokarst and neotectonics. Our findings suggest that thermo-erosional valleys are prominent, hitherto overlooked permafrost degradation landforms that add to impacts on biogeochemical cycling, sediment transport, and hydrology in the degrading Siberian Yedoma Ice Complex. KW - geomorphology KW - periglacial landscapes KW - permafrost degradation KW - thermal KW - erosion KW - valley distribution KW - Yedoma Ice Complex Y1 - 2020 U6 - https://doi.org/10.1002/ppp.2087 SN - 1045-6740 SN - 1099-1530 VL - 32 IS - 1 SP - 59 EP - 75 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Angelopoulos, Michael A1 - Overduin, Pier Paul A1 - Westermann, Sebastian A1 - Tronicke, Jens A1 - Strauss, Jens A1 - Schirrmeister, Lutz A1 - Biskaborn, Boris K. A1 - Liebner, Susanne A1 - Maksimov, Georgii A1 - Grigoriev, Mikhail N. A1 - Grosse, Guido T1 - Thermokarst lake to lagoon transitions in Eastern Siberia BT - do submerged taliks refreeze? JF - Journal of geophysical research : Earth surface N2 - As the Arctic coast erodes, it drains thermokarst lakes, transforming them into lagoons, and, eventually, integrates them into subsea permafrost. Lagoons represent the first stage of a thermokarst lake transition to a marine setting and possibly more saline and colder upper boundary conditions. In this research, borehole data, electrical resistivity surveying, and modeling of heat and salt diffusion were carried out at Polar Fox Lagoon on the Bykovsky Peninsula, Siberia. Polar Fox Lagoon is a seasonally isolated water body connected to Tiksi Bay through a channel, leading to hypersaline waters under the ice cover. The boreholes in the center of the lagoon revealed floating ice and a saline cryotic bed underlain by a saline cryotic talik, a thin ice-bearing permafrost layer, and unfrozen ground. The bathymetry showed that most of the lagoon had bedfast ice in spring. In bedfast ice areas, the electrical resistivity profiles suggested that an unfrozen saline layer was underlain by a thick layer of refrozen talik. The modeling showed that thermokarst lake taliks can refreeze when submerged in saltwater with mean annual bottom water temperatures below or slightly above 0 degrees C. This occurs, because the top-down chemical degradation of newly formed ice-bearing permafrost is slower than the refreezing of the talik. Hence, lagoons may precondition taliks with a layer of ice-bearing permafrost before encroachment by the sea, and this frozen layer may act as a cap on gas migration out of the underlying talik. KW - thermokarst lake KW - talik KW - lagoon KW - subsea permafrost KW - salt diffusion KW - Siberia Y1 - 2020 U6 - https://doi.org/10.1029/2019JF005424 SN - 2169-9003 SN - 2169-9011 VL - 125 IS - 10 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Opel, Thomas A1 - Murton, Julian B. A1 - Wetterich, Sebastian A1 - Meyer, Hanno A1 - Ashastina, Kseniia A1 - Günther, Frank A1 - Grotheer, Hendrik A1 - Mollenhauer, Gesine A1 - Danilov, Petr P. A1 - Boeskorov, Vasily A1 - Savvinov, Grigoriy N. A1 - Schirrmeister, Lutz T1 - Past climate and continentality inferred from ice wedges at Batagay Highlands, interior Yakutia JF - Climate of the past : an interactive open access journal of the European Geosciences Union N2 - Ice wedges in the Yana Highlands of interior Yakutia - the most continental region of the Northern Hemisphere - were investigated to elucidate changes in winter climate and continentality that have taken place since the Middle Pleistocene. The Batagay megaslump exposes ice wedges and composite wedges that were sampled from three cryostratigraphic units: the lower ice complex of likely pre-Marine Isotope Stage (MIS) 6 age, the upper ice complex (Yedoma) and the upper sand unit (both MIS 3 to 2). A terrace of the nearby Adycha River provides a Late Holocene (MIS 1) ice wedge that serves as a modern reference for interpretation. The stable-isotope composition of ice wedges in the MIS 3 upper ice complex at Batagay is more depleted (mean delta O-18 about -35 parts per thousand) than those from 17 other ice-wedge study sites across coastal and central Yakutia. This observation points to lower winter temperatures and therefore higher continentality in the Yana Highlands during MIS 3. Likewise, more depleted isotope values are found in Holocene wedge ice (mean delta O-18 about -29 parts per thousand) compared to other sites in Yakutia. Ice-wedge isotopic signatures of the lower ice complex mean delta O-18 about -33 parts per thousand) and of the MIS 3-2 upper sand unit (mean delta O-18 from about -33 parts per thousand to -30 parts per thousand) are less distinctive regionally. The latter unit preserves traces of fast formation in rapidly accumulating sand sheets and of post-depositional isotopic fractionation. Y1 - 2019 U6 - https://doi.org/10.5194/cp-15-1443-2019 SN - 1814-9324 SN - 1814-9332 VL - 15 IS - 4 SP - 1443 EP - 1461 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Wetterich, Sebastian A1 - Rudaya, Natalia A1 - Kuznetsov, Vladislav A1 - Maksimov, Fedor A1 - Opel, Thomas A1 - Meyer, Hanno A1 - Günther, Frank A1 - Bobrov, Anatoly A1 - Raschke, Elena A1 - Zimmermann, Heike Hildegard A1 - Strauss, Jens A1 - Starikova, Anna A1 - Fuchs, Margret A1 - Schirrmeister, Lutz T1 - Ice Complex formation on Bol'shoy Lyakhovsky Island (New Siberian Archipelago, East Siberian Arctic) since about 200 ka JF - Quaternary research : an interdisciplinary journal N2 - Late Quaternary landscapes of unglaciated Beringia were largely shaped by ice-wedge polygon tundra. Ice Complex (IC) strata preserve such ancient polygon formations. Here we report on the Yukagir IC from Bol'shoy Lyakhovsky Island in northeastern Siberia and suggest that new radioisotope disequilibria (230Th/U) dates of the Yukagir IC peat confirm its formation during the Marine Oxygen Isotope Stage (MIS) 7a–c interglacial period. The preservation of the ice-rich Yukagir IC proves its resilience to last interglacial and late glacial–Holocene warming. This study compares the Yukagir IC to IC strata of MIS 5, MIS 3, and MIS 2 ages exposed on Bol'shoy Lyakhovsky Island. Besides high intrasedimental ice content and syngenetic ice wedges intersecting silts, sandy silts, the Yukagir IC is characterized by high organic matter (OM) accumulation and low OM decomposition of a distinctive Drepanocladus moss-peat. The Yukagir IC pollen data reveal grass-shrub-moss tundra indicating rather wet summer conditions similar to modern ones. The stable isotope composition of Yukagir IC wedge ice is similar to those of the MIS 5 and MIS 3 ICs pointing to similar atmospheric moisture generation and transport patterns in winter. IC data from glacial and interglacial periods provide insights into permafrost and climate dynamics since about 200 ka. KW - Cryostratigraphy KW - Ice wedges KW - Stable isotopes KW - Pollen KW - Radioisotope disequilibria dating KW - Beringia Y1 - 2019 U6 - https://doi.org/10.1017/qua.2019.6 SN - 0033-5894 SN - 1096-0287 VL - 92 IS - 2 SP - 530 EP - 548 PB - Cambridge Univ. Press CY - New York 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 - TY - JOUR A1 - Schirrmeister, Lutz A1 - Bobrov, Anatoly A1 - Raschke, Elena A1 - Herzschuh, Ulrike A1 - Strauss, Jens A1 - Pestryakova, Luidmila Agafyevna A1 - Wetterich, Sebastian T1 - Late Holocene ice-wedge polygon dynamics in northeastern Siberian coastal lowlands JF - Arctic, antarctic, and alpine research : an interdisciplinary journal N2 - Ice-wedge polygons are common features of northeastern Siberian lowland periglacial tundra landscapes. To deduce the formation and alternation of ice-wedge polygons in the Kolyma Delta and in the Indigirka Lowland, we studied shallow cores, up to 1.3 m deep, from polygon center and rim locations. The formation of well-developed low-center polygons with elevated rims and wet centers is shown by the beginning of peat accumulation, increased organic matter contents, and changes in vegetation cover from Poaceae-, Alnus-, and Betula-dominated pollen spectra to dominating Cyperaceae and Botryoccocus presence, and Carex and Drepanocladus revolvens macro-fossils. Tecamoebae data support such a change from wetland to open-water conditions in polygon centers by changes from dominating eurybiontic and sphagnobiontic to hydrobiontic species assemblages. The peat accumulation indicates low-center polygon formation and started between 2380 +/- 30 and 1676 +/- 32 years before present (BP) in the Kolyma Delta. We recorded an opposite change from open-water to wetland conditions because of rim degradation and consecutive high-center polygon formation in the Indigirka Lowland between 2144 +/- 33 and 1632 +/- 32 years BP. The late Holocene records of polygon landscape development reveal changes in local hydrology and soil moisture. KW - Permafrost KW - cryolithology KW - radiocarbon dating KW - paleoecology KW - rhizopods KW - pollen KW - plant macro-fossils Y1 - 2018 U6 - https://doi.org/10.1080/15230430.2018.1462595 SN - 1523-0430 SN - 1938-4246 VL - 50 IS - 1 PB - Institute of Arctic and Alpine Research, University of Colorado CY - Boulder ER - TY - GEN A1 - Schirrmeister, Lutz A1 - Bobrov, Anatoly A1 - Raschke, Elena A1 - Herzschuh, Ulrike A1 - Strauss, Jens A1 - Pestryakova, Luidmila Agafyevna A1 - Wetterich, Sebastian T1 - Late Holocene ice-wedge polygon dynamics in northeastern Siberian coastal lowlands T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Ice-wedge polygons are common features of northeastern Siberian lowland periglacial tundra landscapes. To deduce the formation and alternation of ice-wedge polygons in the Kolyma Delta and in the Indigirka Lowland, we studied shallow cores, up to 1.3 m deep, from polygon center and rim locations. The formation of well-developed low-center polygons with elevated rims and wet centers is shown by the beginning of peat accumulation, increased organic matter contents, and changes in vegetation cover from Poaceae-, Alnus-, and Betula-dominated pollen spectra to dominating Cyperaceae and Botryoccocus presence, and Carex and Drepanocladus revolvens macro-fossils. Tecamoebae data support such a change from wetland to open-water conditions in polygon centers by changes from dominating eurybiontic and sphagnobiontic to hydrobiontic species assemblages. The peat accumulation indicates low-center polygon formation and started between 2380 +/- 30 and 1676 +/- 32 years before present (BP) in the Kolyma Delta. We recorded an opposite change from open-water to wetland conditions because of rim degradation and consecutive high-center polygon formation in the Indigirka Lowland between 2144 +/- 33 and 1632 +/- 32 years BP. The late Holocene records of polygon landscape development reveal changes in local hydrology and soil moisture. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 719 KW - permafrost KW - cryolithology KW - radiocarbon dating KW - paleoecology KW - rhizopods KW - pollen KW - plant macro-fossils Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-426603 SN - 1866-8372 IS - 719 ER - TY - JOUR A1 - Zimmermann, Heike Hildegard A1 - Raschke, Elena A1 - Epp, Laura Saskia A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Schirrmeister, Lutz A1 - Schwamborn, Georg A1 - Herzschuh, Ulrike T1 - The history of tree and shrub taxa on Bol'shoy Lyakhovsky Island (New Siberian Archipelago) since the Last Interglacial Uncovered by Sedimentary Ancient DNA and Pollen Data JF - Genes N2 - Ecosystem boundaries, such as the Arctic-Boreal treeline, are strongly coupled with climate and were spatially highly dynamic during past glacial-interglacial cycles. Only a few studies cover vegetation changes since the last interglacial, as most of the former landscapes are inundated and difficult to access. Using pollen analysis and sedimentary ancient DNA (sedaDNA) metabarcoding, we reveal vegetation changes on Bol’shoy Lyakhovsky Island since the last interglacial from permafrost sediments. Last interglacial samples depict high levels of floral diversity with the presence of trees (Larix, Picea, Populus) and shrubs (Alnus, Betula, Ribes, Cornus, Saliceae) on the currently treeless island. After the Last Glacial Maximum, Larix re-colonised the island but disappeared along with most shrub taxa. This was probably caused by Holocene sea-level rise, which led to increased oceanic conditions on the island. Additionally, we applied two newly developed larch-specific chloroplast markers to evaluate their potential for tracking past population dynamics from environmental samples. The novel markers were successfully re-sequenced and exhibited two variants of each marker in last interglacial samples. SedaDNA can track vegetation changes as well as genetic changes across geographic space through time and can improve our understanding of past processes that shape modern patterns. KW - sedaDNA KW - metabarcoding KW - trnL KW - single-nucleotide polymorphism (SNP) KW - treeline KW - MIS 5 to 1 KW - permafrost deposits KW - radiocarbon ages KW - palaeoenvironment KW - Larix Y1 - 2017 U6 - https://doi.org/10.3390/genes8100273 SN - 2073-4425 VL - 8 IS - 10 SP - 273 PB - MDPI CY - Basel ER - TY - JOUR A1 - Zimmermann, Heike Hildegard A1 - Raschke, Elena A1 - Epp, Laura Saskia A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Schwamborn, Georg A1 - Schirrmeister, Lutz A1 - Overduin, Pier Paul A1 - Herzschuh, Ulrike T1 - Sedimentary ancient DNA and pollen reveal the composition of plant organic matter in Late Quaternary permafrost sediments of the Buor Khaya Peninsula (north-eastern Siberia) JF - Biogeosciences N2 - Organic matter deposited in ancient, ice-rich permafrost sediments is vulnerable to climate change and may contribute to the future release of greenhouse gases; it is thus important to get a better characterization of the plant organic matter within such sediments. From a Late Quaternary permafrost sediment core from the Buor Khaya Peninsula, we analysed plant-derived sedimentary ancient DNA (sedaDNA) to identify the taxonomic composition of plant organic matter, and undertook palynological analysis to assess the environmental conditions during deposition. Using sedaDNA, we identified 154 taxa and from pollen and non-pollen palynomorphs we identified 83 taxa. In the deposits dated between 54 and 51 kyr BP, sedaDNA records a diverse low-centred polygon plant community including recurring aquatic pond vegetation while from the pollen record we infer terrestrial open-land vegetation with relatively dry environmental conditions at a regional scale. A fluctuating dominance of either terrestrial or swamp and aquatic taxa in both proxies allowed the local hydrological development of the polygon to be traced. In deposits dated between 11.4 and 9.7 kyr BP (13.4-11.1 cal kyr BP), sedaDNA shows a taxonomic turnover to moist shrub tundra and a lower taxonomic richness compared to the older samples. Pollen also records a shrub tundra community, mostly seen as changes in relative proportions of the most dominant taxa, while a decrease in taxonomic richness was less pronounced compared to sedaDNA. Our results show the advantages of using sedaDNA in combination with palynological analyses when macrofossils are rarely preserved. The high resolution of the sedaDNA record provides a detailed picture of the taxonomic composition of plant-derived organic matter throughout the core, and palynological analyses prove valuable by allowing for inferences of regional environmental conditions. Y1 - 2017 U6 - https://doi.org/10.5194/bg-14-575-2017 SN - 1726-4170 SN - 1726-4189 VL - 14 IS - 3 SP - 575 EP - 596 PB - Copernicus CY - Göttingen ER -