TY - JOUR A1 - Fritz, M. A1 - Deshpande, B. N. A1 - Bouchard, F. A1 - Hogstrom, E. A1 - Malenfant-Lepage, J. A1 - Morgenstern, Anne A1 - Nieuwendam, A. A1 - Oliva, M. A1 - Paquette, M. A1 - Rudy, A. C. A. A1 - Siewert, M. B. A1 - Sjoberg, Y. A1 - Weege, Stefanie T1 - Brief Communication: Future avenues for permafrost science from the perspective of early career researchers JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union N2 - Accelerating climate change and increased economic and environmental interests in permafrost-affected regions have resulted in an acute need for more directed permafrost research. In June 2014, 88 early career researchers convened to identify future priorities for permafrost research. This multidisciplinary forum concluded that five research topics deserve greatest attention: permafrost landscape dynamics, permafrost thermal modeling, integration of traditional knowledge, spatial distribution of ground ice, and engineering issues. These topics underline the need for integrated research across a spectrum of permafrost-related domains and constitute a contribution to the Third International Conference on Arctic Research Planning (ICARP III). Y1 - 2015 U6 - https://doi.org/10.5194/tc-9-1715-2015 SN - 1994-0416 SN - 1994-0424 VL - 9 IS - 4 SP - 1715 EP - 1720 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Ramage, Justine Lucille A1 - Fortier, Daniel A1 - Hugelius, Gustaf A1 - Lantuit, Hugues A1 - Morgenstern, Anne T1 - Distribution of carbon and nitrogen along hillslopes in three valleys on Herschel Island, Yukon Territory, Canada JF - Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution N2 - Thermokarst results from the thawing of ice-rich permafrost and alters the biogeochemical cycling in the Arctic by reworking soil material and redistributing soil organic carbon (SOC) and total nitrogen (TN) along uplands, hillslopes, and lowlands. Understanding the impact of this redistribution is key to better estimating the storage of SOC in permafrost terrains. However, there are insufficient studies quantifying long-term impacts of thaw processes on the distribution of SOC and TN along hillslopes. We address this issue by providing estimates of SOC and TN stocks along the hillslopes of three valleys located on Herschel Island (Yukon, Canada), and by discussing the impact of hillslope thermokarst on the variability of SOC and TN stocks. We found that the average SOC and TN 0-100 cm stocks in the valleys were 26.4 +/- 8.9 kg C m(-2) and 2.1 +/- 0.6 kg N m(-2). We highlight the strong variability in the soils physical and geochemical properties within hillslope positions. High SOC stocks were found at the summits, essentially due to burial of organic matter by cryoturbation, and at the toeslopes due to impeded drainage which favored peat formation and SOC accumulation. The average carbon-to-nitrogen ratio in the valleys was 12.9, ranging from 9.7 to 18.9, and was significantly higher at the summits compared to the backslopes and footslopes (p < 0.05), suggesting a degradation of SOC downhill. Carbon and nitrogen contents and stocks were significantly lower on 16% of the sites that were previously affected by hillslope thermokarst (p < 0.05). Our results showed that lateral redistribution of SOC and TN due to hillslope thermokarst has a strong impact on the SOC storage in ice-rich permafrost terrains. KW - Hillslope thermokarst KW - Soil organic carbon storage KW - Catchment geomorphology KW - Permafrost degradation Y1 - 2019 U6 - https://doi.org/10.1016/j.catena.2019.02.029 SN - 0341-8162 SN - 1872-6887 VL - 178 SP - 132 EP - 140 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ramage, Justine Lucille A1 - Irrgang, Anna Maria A1 - Morgenstern, Anne A1 - Lantuit, Hugues T1 - Increasing coastal slump activity impacts the release of sediment and organic carbon into the Arctic Ocean JF - Biogeosciences N2 - Retrogressive thaw slumps (RTSs) are among the most active thermokarst landforms in the Arctic and deliver a large amount of material to the Arctic Ocean. However, their contribution to the organic carbon (OC) budget is unknown. We provide the first estimate of the contribution of RTSs to the nearshore OC budget of the Yukon Coast, Canada, and describe the evolution of coastal RTSs between 1952 and 2011 in this area. We (1) describe the evolution of RTSs between 1952 and 2011; (2) calculate the volume of eroded material and stocks of OC mobilized through slumping, including soil organic carbon (SOC) and dissolved organic carbon (DOC); and (3) estimate the OC fluxes mobilized through slumping between 1972 and 2011. We identified RTSs using high- resolution satellite imagery from 2011 and geocoded aerial photographs from 1952 and 1972. To estimate the volume of eroded material, we applied spline interpolation on an airborne lidar dataset acquired in July 2013. We inferred the stocks of mobilized SOC and DOC from existing related literature. Our results show a 73% increase in the number of RTSs and 14% areal expansion between 1952 and 2011. In the study area, RTSs displaced at least 16.6 x 10(6) m(3) of material, 53% of which was ice, and mobilized 145.9 x 10(6) kg of OC. Between 1972 and 2011, 49 RTSs displaced 8.6 x 10(3) m(3) yr(-1) of material, adding 0.6% to the OC flux released by coastal retreat along the Yukon Coast. Our results show that the contribution of RTSs to the nearshore OC budget is non-negligible and should be included when estimating the quantity of OC released from the Arctic coast to the ocean. Y1 - 2018 U6 - https://doi.org/10.5194/bg-15-1483-2018 SN - 1726-4170 SN - 1726-4189 VL - 15 IS - 5 SP - 1483 EP - 1495 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Stolpmann, Lydia A1 - Mollenhauer, Gesine A1 - Morgenstern, Anne A1 - Hammes, Jens S. A1 - Boike, Julia A1 - Overduin, Pier Paul A1 - Grosse, Guido T1 - Origin and pathways of dissolved organic carbon in a small catchment in the Lena River Delta JF - Frontiers in Earth Science N2 - The Arctic is rich in aquatic systems and experiences rapid warming due to climate change. The accelerated warming causes permafrost thaw and the mobilization of organic carbon. When dissolved organic carbon is mobilized, this DOC can be transported to aquatic systems and degraded in the water bodies and further downstream. Here, we analyze the influence of different landscape components on DOC concentrations and export in a small (6.45 km(2)) stream catchment in the Lena River Delta. The catchment includes lakes and ponds, with the flow path from Pleistocene yedoma deposits across Holocene non-yedoma deposits to the river outlet. In addition to DOC concentrations, we use radiocarbon dating of DOC as well as stable oxygen and hydrogen isotopes (delta O-18 and delta D) to assess the origin of DOC. We find significantly higher DOC concentrations in the Pleistocene yedoma area of the catchment compared to the Holocene non-yedoma area with medians of 5 and 4.5 mg L-1 (p < 0.05), respectively. When yedoma thaw streams with high DOC concentration reach a large yedoma thermokarst lake, we observe an abrupt decrease in DOC concentration, which we attribute to dilution and lake processes such as mineralization. The DOC ages in the large thermokarst lake (between 3,428 and 3,637 C-14 y BP) can be attributed to a mixing of mobilized old yedoma and Holocene carbon. Further downstream after the large thermokarst lake, we find progressively younger DOC ages in the stream water to its mouth, paired with decreasing DOC concentrations. This process could result from dilution with leaching water from Holocene deposits and/or emission of ancient yedoma carbon to the atmosphere. Our study shows that thermokarst lakes and ponds may act as DOC filters, predominantly by diluting incoming waters of higher DOC concentrations or by re-mineralizing DOC to CO2 and CH4. Nevertheless, our results also confirm that the small catchment still contributes DOC on the order of 1.2 kg km(-2) per day from a permafrost landscape with ice-rich yedoma deposits to the Lena River. KW - Arctic lakes KW - ice complex KW - yedoma KW - thermokarst lakes KW - DOC KW - aquatic carbon cycle KW - permafrost KW - radiocarbon dating Y1 - 2022 U6 - https://doi.org/10.3389/feart.2021.759085 SN - 2296-6463 VL - 9 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Heim, Birgit A1 - Lisovski, Simeon A1 - Wieczorek, Mareike A1 - Morgenstern, Anne A1 - Juhls, Bennet A1 - Shevtsova, Iuliia A1 - Kruse, Stefan A1 - Boike, Julia A1 - Fedorova, Irina A1 - Herzschuh, Ulrike T1 - Spring snow cover duration and tundra greenness in the Lena Delta, Siberia BT - two decades of MODIS satellite time series (2001-2021) JF - Environmental research letters N2 - The Lena Delta in Siberia is the largest delta in the Arctic and as a snow-dominated ecosystem particularly vulnerable to climate change. Using the two decades of MODerate resolution Imaging Spectroradiometer satellite acquisitions, this study investigates interannual and spatial variability of snow-cover duration and summer vegetation vitality in the Lena Delta. We approximated snow by the application of the normalized difference snow index and vegetation greenness by the normalized difference vegetation index (NDVI). We consolidated the analyses by integrating reanalysis products on air temperature from 2001 to 2021, and air temperature, ground temperature, and the date of snow-melt from time-lapse camera (TLC) observations from the Samoylov observatory located in the central delta. We extracted spring snow-cover duration determined by a latitudinal gradient. The 'regular year' snow-melt is transgressing from mid-May to late May within a time window of 10 days across the delta. We calculated yearly deviations per grid cell for two defined regions, one for the delta, and one focusing on the central delta. We identified an ensemble of early snow-melt years from 2012 to 2014, with snow-melt already starting in early May, and two late snow-melt years in 2004 and 2017, with snow-melt starting in June. In the times of TLC recording, the years of early and late snow-melt were confirmed. In the three summers after early snow-melt, summer vegetation greenness showed neither positive nor negative deviations. Whereas, vegetation greenness was reduced in 2004 after late snow-melt together with the lowest June monthly air temperature of the time series record. Since 2005, vegetation greenness is rising, with maxima in 2018 and 2021. The NDVI rise since 2018 is preceded by up to 4 degrees C warmer than average June air temperature. The ongoing operation of satellite missions allows to monitor a wide range of land surface properties and processes that will provide urgently needed data in times when logistical challenges lead to data gaps in land-based observations in the rapidly changing Arctic. KW - Arctic vegetation KW - tundra KW - snow cover duration KW - NDVI KW - NDSI KW - MODIS KW - Lena Delta Y1 - 2022 U6 - https://doi.org/10.1088/1748-9326/ac8066 SN - 1748-9326 VL - 17 IS - 8 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Ramage, Justine Lucille A1 - Irrgang, Anna Maria A1 - Herzschuh, Ulrike A1 - Morgenstern, Anne A1 - Couture, Nicole A1 - Lantuit, Hugues T1 - Terrain controls on the occurrence of coastal retrogressive thaw slumps along the Yukon Coast, Canada JF - Journal of geophysical research : Earth surface N2 - Retrogressive thaw slumps (RTSs) are among the most active landforms in the Arctic; their number has increased significantly over the past decades. While processes initiating discrete RTSs are well identified, the major terrain controls on the development of coastal RTSs at a regional scale are not yet defined. Our research reveals the main geomorphic factors that determine the development of RTSs along a 238km segment of the Yukon Coast, Canada. We (1) show the current extent of RTSs, (2) ascertain the factors controlling their activity and initiation, and (3) explain the spatial differences in the density and areal coverage of RTSs. We mapped and classified 287 RTSs using high-resolution satellite images acquired in 2011. We highlighted the main terrain controls over their development using univariate regression trees model. Coastal geomorphology influenced both the activity and initiation of RTSs: active RTSs and RTSs initiated after 1972 occurred primarily on terrains with slope angles greater than 3.9 degrees and 5.9 degrees, respectively. The density and areal coverage of RTSs were constrained by the volume and thickness of massive ice bodies. Differences in rates of coastal change along the coast did not affect the model. We infer that rates of coastal change averaged over a 39year period are unable to reflect the complex relationship between RTSs and coastline dynamics. We emphasize the need for large-scale studies of RTSs to evaluate their impact on the ecosystem and to measure their contribution to the global carbon budget. Plain Language Summary Retrogressive thaw slumps, henceforth slumps are a type of landslides that occur when permafrost thaws. Slumps are active landforms: they develop quickly and extend over several hectares. Satellite imagery allows to map such slumps over large areas. Our research shows where slumps develop along a 238 km segment of the Yukon Coast in Canada and explains which environments are most suitable for slump occurrence. We found that active and newly developed slumps were triggered where coastal slopes were greater than 3.9 degrees and 5.9 degrees, respectively. We explain that coastal erosion influences the development of slumps by modifying coastal slopes. We found that the highest density of slumps as well as the largest slumps occurred on terrains with high amounts of ice bodies in the ground. This study provides tools to better identify areas in the Arctic that are prone to slump development. KW - permafrost degradation KW - retrogressive thaw slumps KW - coastal erosion KW - Arctic KW - coastal geomorphology Y1 - 2017 U6 - https://doi.org/10.1002/2017JF004231 SN - 2169-9003 SN - 2169-9011 VL - 122 SP - 1619 EP - 1634 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Tanski, George A1 - Bergstedt, Helena A1 - Bevington, Alexandre A1 - Bonnaventure, Philip A1 - Bouchard, Frederic A1 - Coch, Caroline A1 - Dumais, Simon A1 - Evgrafova, Alevtina A1 - Frauenfeld, Oliver W. A1 - Frederick, Jennifer A1 - Fritz, Michael A1 - Frolov, Denis A1 - Harder, Silvie A1 - Hartmeyer, Ingo A1 - Heslop, Joanne A1 - Hoegstroem, Elin A1 - Johansson, Margareta A1 - Kraev, Gleb A1 - Kuznetsova, Elena A1 - Lenz, Josefine A1 - Lupachev, Alexey A1 - Magnin, Florence A1 - Martens, Jannik A1 - Maslakov, Alexey A1 - Morgenstern, Anne A1 - Nieuwendam, Alexandre A1 - Oliva, Marc A1 - Radosavljevi, Boris A1 - Ramage, Justine Lucille A1 - Schneider, Andrea A1 - Stanilovskaya, Julia A1 - Strauss, Jens A1 - Trochim, Erin A1 - Vecellio, Daniel J. A1 - Weber, Samuel A1 - Lantuit, Hugues T1 - The Permafrost Young Researchers Network (PYRN) is getting older BT - The past, present, and future of our evolving community JF - Polar record N2 - 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. KW - Early-career scientists KW - Education KW - IPY KW - International Polar Year KW - Outreach KW - Permafrost Young Researchers Network KW - PYRN KW - Science communication Y1 - 2019 U6 - https://doi.org/10.1017/S0032247418000645 SN - 0032-2474 SN - 1475-3057 VL - 55 IS - 4 SP - 216 EP - 219 PB - Cambridge Univ. Press CY - New York 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 -