@article{TanskiBergstedtBevingtonetal.2019,
  author    = {Tanski, George and Bergstedt, Helena and Bevington, Alexandre and Bonnaventure, Philip and Bouchard, Frederic and Coch, Caroline and Dumais, Simon and Evgrafova, Alevtina and Frauenfeld, Oliver W. and Frederick, Jennifer and Fritz, Michael and Frolov, Denis and Harder, Silvie and Hartmeyer, Ingo and Heslop, Joanne and Hoegstroem, Elin and Johansson, Margareta and Kraev, Gleb and Kuznetsova, Elena and Lenz, Josefine and Lupachev, Alexey and Magnin, Florence and Martens, Jannik and Maslakov, Alexey and Morgenstern, Anne and Nieuwendam, Alexandre and Oliva, Marc and Radosavljevi, Boris and Ramage, Justine Lucille and Schneider, Andrea and Stanilovskaya, Julia and Strauss, Jens and Trochim, Erin and Vecellio, Daniel J. and Weber, Samuel and Lantuit, Hugues},
  title     = {The Permafrost Young Researchers Network (PYRN) is getting older},
  series = {Polar record},
  volume    = {55},
  journal   = {Polar record},
  number    = {4},
  publisher = {Cambridge Univ. Press},
  address   = {New York},
  issn      = {0032-2474},
  doi       = {10.1017/S0032247418000645},
  pages     = {216 -- 219},
  year      = {2019},
  abstract  = {A lasting legacy of the International Polar Year (IPY) 2007-2008 was the promotion of the Permafrost Young Researchers Network (PYRN), initially an IPY outreach and education activity by the International Permafrost Association (IPA). With the momentum of IPY, PYRN developed into a thriving network that still connects young permafrost scientists, engineers, and researchers from other disciplines. This research note summarises (1) PYRN's development since 2005 and the IPY's role, (2) the first 2015 PYRN census and survey results, and (3) PYRN's future plans to improve international and interdisciplinary exchange between young researchers. The review concludes that PYRN is an established network within the polar research community that has continually developed since 2005. PYRN's successful activities were largely fostered by IPY. With >200 of the 1200 registered members active and engaged, PYRN is capitalising on the availability of social media tools and rising to meet environmental challenges while maintaining its role as a successful network honouring the legacy of IPY.},
  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}
}
@article{FuchsLenzJocketal.2019,
  author    = {Fuchs, Matthias and Lenz, Josefine and Jock, Suzanne and Nitze, Ingmar and Jones, Benjamin M. and Strauss, Jens and G{\"u}nther, Frank and Grosse, Guido},
  title     = {Organic carbon and nitrogen stocks along a thermokarst lake sequence in Arctic Alaska},
  series = {Journal of geophysical research : Biogeosciences},
  volume    = {124},
  journal   = {Journal of geophysical research : Biogeosciences},
  number    = {5},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {2169-8953},
  doi       = {10.1029/2018JG004591},
  pages     = {1230 -- 1247},
  year      = {2019},
  abstract  = {Thermokarst lake landscapes are permafrost regions, which are prone to rapid (on seasonal to decadal time scales) changes, affecting carbon and nitrogen cycles. However, there is a high degree of uncertainty related to the balance between carbon and nitrogen cycling and storage. We collected 12 permafrost soil cores from six drained thermokarst lake basins (DTLBs) along a chronosequence north of Teshekpuk Lake in northern Alaska and analyzed them for carbon and nitrogen contents. For comparison, we included three lacustrine cores from an adjacent thermokarst lake and one soil core from a non thermokarst affected remnant upland. This allowed to calculate the carbon and nitrogen stocks of the three primary landscape units (DTLB, lake, and upland), to reconstruct the landscape history, and to analyze the effect of thermokarst lake formation and drainage on carbon and nitrogen stocks. We show that carbon and nitrogen contents and the carbon-nitrogen ratio are considerably lower in sediments of extant lakes than in the DTLB or upland cores indicating degradation of carbon during thermokarst lake formation. However, we found similar amounts of total carbon and nitrogen stocks due to the higher density of lacustrine sediments caused by the lack of ground ice compared to DTLB sediments. In addition, the radiocarbon-based landscape chronology for the past 7,000years reveals five successive lake stages of partially, spatially overlapping DTLBs in the study region, reflecting the dynamic nature of ice-rich permafrost deposits. With this study, we highlight the importance to include these dynamic landscapes in future permafrost carbon feedback models. Plain Language Summary When permanently frozen soils (permafrost) contain ice-rich sediments, the thawing of this permafrost causes the surface to sink, which may result in lake formation. This process, the thaw of ice-rich permafrost and melting of ground ice leads to characteristic landforms-known as thermokarst. Once such a thaw process is initiated in ice-rich sediments, a thaw lake forms and grows by shoreline erosion, eventually expanding until a drainage pathway is encountered and the lake eventually drains, resulting in a drained thermokarst lake basin. In our study, we show that such a thermokarst-affected landscape north of Teshekpuk Lake in northern Alaska is shaped by repeated thaw lake formation and lake drainage events during the past 7,000years, highlighting the dynamic nature of these landscapes. These landscape-scale processes have a big effect on the carbon and nitrogen stored in permafrost soils. We show that large amounts of carbon (>45kg C/m(2)) and nitrogen (>2.6kg N/m(2)) are stored in unfrozen lake sediments and in frozen soil sediments. The findings are important when considering the potential effect that permafrost thaw has for the global climate through releasing carbon and nitrogen, which was frozen and therefore locked away for millennia, from the active carbon cycle.},
  language  = {en}
}