ALBERT

Description: Ice rich Yedoma-dominated landscapes store considerable amounts of organic carbon (C) and nitrogen (N) and are vulnerable to degradation under climate warming. We investigate the C and N pools in two thermokarst-affected Yedoma landscapes - on Sobo-Sise Island and on Bykovsky Peninsula in the North of East Siberia. Soil cores up to three meters depth were collected along geomorphic gradients and analysed for organic C and N contents. A high vertical sampling density in the profiles allowed the calculation of C and N stocks for short soil column intervals and enhanced understanding of within-core parameter variability. Profile-level C and N stocks were scaled to the landscape level based on landform classifications from five-meter resolution, multispectral RapidEye satellite imagery. Mean landscape C and N storage in the first meter of soil for Sobo-Sise Island is estimated to be 20.2 kg C/m**-2 and 1.8 kg N/m**-2 and for Bykovsky Peninsula 25.9 kg C/m**-2 and 2.2 kg N/m**-2. Radiocarbon dating demonstrates the Holocene age of thermokarst basin deposits but also suggests the presence of thick Holocene aged cover layers which can reach up to two meters on top of intact Yedoma landforms. Reconstructed sedimentation rates of 0.10 mm/yr - 0.57 mm/yr suggest sustained mineral soil accumulation across all investigated landforms. Both Yedoma and thermokarst landforms are characterized by limited accumulation of organic soil layers (peat). We further estimate that an active layer deepening by about 100 cm will increase organic C availability in a seasonally thawed state in the two study areas by ~5.8 Tg (13.2 kg C/m**-2). Our study demonstrates the importance of increasing the number of C and N storage inventories in ice-rich Yedoma and thermokarst environments in order to account for high variability of permafrost and thermokarst environments in pan-permafrost soil C and N pool estimates.

Description: This data set describes the soil core and sample characteristics from the Ikpikpuk and Fish Creek river delta on the Arctic Coastal Plain in northern Alaska. The collection of the permafrost soil cores and the analysis of the samples are described in Fuchs et al. (2018). Sedimentary and geochemical characteristics of two small permafrost-dominated Arctic river deltas in northern Alaska. This data compilation consists of two data set. The first data set describes the properties of the collected permafrost soil cores from the Ikpikpuk river (IKP) and Fish Creek river (FCR) delta. This includes the coordinates of the nine coring locations, the field measurements of the active- and organic layer thickness at the coring locations, and the length of the collected permafrost core. In addition, soil organic carbon and soil nitrogen stocks and densities derived from the laboratory analyses for the reference depths 0-30 cm, 0-100 cm, 0-150 cm and 0-200 cm are presented in kg C m-2 and in kg C m-3. The second data set provides the raw laboratory data for all the samples of the nine collected permafrost cores in the Ikpikpuk and Fish Creek River Delta. All laboratory analyzes were carried out at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam. The third data set presents the results from the radiocarbon dating of chosen samples from five different permafrost cores. This includes the AMS radiocarbon date and the calibrated age of a sample. In addition, the sediment and organic carbon accumulation rates for the dated samples are included. This data set allows to calculate the total carbon and nitrogen storage in two small Arctic river deltas (IKP and FCR) for the first two meter of soil and enlarges the available permafrost cores for Arctic river delta deposits.

Description: Vast portions of Arctic and sub-Arctic Siberia, Alaska and the Yukon Territory are covered by ice-rich silty to sandy deposits that are containing large ice wedges, resulting from syngenetic sedimentation and freezing. Accompanied by wedge-ice growth in polygonal landscapes, the sedimentation process was driven by cold continental climatic and environmental conditions in unglaciated regions during the late Pleistocene, inducing the accumulation of the unique Yedoma deposits up to 〉50 meters thick. Because of fast incorporation of organic material into syngenetic permafrost during its formation, Yedoma deposits include well-preserved organic matter. Ice-rich deposits like Yedoma are especially prone to degradation triggered by climate changes or human activity. When Yedoma deposits degrade, large amounts of sequestered organic carbon as well as other nutrients are released and become part of active biogeochemical cycling. This could be of global significance for future climate warming as increased permafrost thaw is likely to lead to a positive feedback through enhanced greenhouse gas fluxes. Therefore, a detailed assessment of the current Yedoma deposit coverage and its volume is of importance to estimate its potential response to future climate changes. We synthesized the map of the coverage and thickness estimation, which will provide critical data needed for further research. In particular, this preliminary Yedoma map is a great step forward to understand the spatial heterogeneity of Yedoma deposits and its regional coverage. There will be further applications in the context of reconstructing paleo-environmental dynamics and past ecosystems like the mammoth-steppe-tundra, or ground ice distribution including future thermokarst vulnerability. Moreover, the map will be a crucial improvement of the data basis needed to refine the present-day Yedoma permafrost organic carbon inventory, which is assumed to be between 83±12 (Strauss et al., 2013, doi:10.1002/2013GL058088) and 129±30 (Walter Anthony et al., 2014, doi:10.1038/nature13560) gigatonnes (Gt) of organic carbon in perennially-frozen archives. Hence, here we synthesize data on the circum-Arctic and sub-Arctic distribution and thickness of Yedoma for compiling a preliminary circum-polar Yedoma map. For compiling this map, we used (1) maps of the previous Yedoma coverage estimates, (2) included the digitized areas from Grosse et al. (2013) as well as extracted areas of potential Yedoma distribution from additional surface geological and Quaternary geological maps (1.: 1:500,000: Q-51-V,G; P-51-A,B; P-52-A,B; Q-52-V,G; P-52-V,G; Q-51-A,B; R-51-V,G; R-52-V,G; R-52-A,B; 2.: 1:1,000,000: P-50-51; P-52-53; P-58-59; Q-42-43; Q-44-45; Q-50-51; Q-52-53; Q-54-55; Q-56-57; Q-58-59; Q-60-1; R-(40)-42; R-43-(45); R-(45)-47; R-48-(50); R-51; R-53-(55); R-(55)-57; R-58-(60); S-44-46; S-47-49; S-50-52; S-53-55; 3.: 1:2,500,000: Quaternary map of the territory of Russian Federation, 4.: Alaska Permafrost Map). The digitalization was done using GIS techniques (ArcGIS) and vectorization of raster Images (Adobe Photoshop and Illustrator). Data on Yedoma thickness are obtained from boreholes and exposures reported in the scientific literature. The map and database are still preliminary and will have to undergo a technical and scientific vetting and review process. In their current form, we included a range of attributes for Yedoma area polygons based on lithological and stratigraphical information from the original source maps as well as a confidence level for our classification of an area as Yedoma (3 stages: confirmed, likely, or uncertain). In its current version, our database includes more than 365 boreholes and exposures and more than 2000 digitized Yedoma areas. We expect that the database will continue to grow. In this preliminary stage, we estimate the Northern Hemisphere Yedoma deposit area to cover approximately 625,000 km². We estimate that 53% of the total Yedoma area today is located in the tundra zone, 47% in the taiga zone. Separated from west to east, 29% of the Yedoma area is found in North America and 71 % in North Asia. The latter include 9% in West Siberia, 11% in Central Siberia, 44% in East Siberia and 7% in Far East Russia. Adding the recent maximum Yedoma region (including all Yedoma uplands, thermokarst lakes and basins, and river valleys) of 1.4 million km² (Strauss et al., 2013, doi:10.1002/2013GL058088) and postulating that Yedoma occupied up to 80% of the adjacent formerly exposed and now flooded Beringia shelves (1.9 million km², down to 125 m below modern sea level, between 105°E - 128°W and 〉68°N), we assume that the Last Glacial Maximum Yedoma region likely covered more than 3 million km² of Beringia. Acknowledgements: This project is part of the Action Group "The Yedoma Region: A Synthesis of Circum-Arctic Distribution and Thickness" (funded by the International Permafrost Association (IPA) to J. Strauss) and is embedded into the Permafrost Carbon Network (working group Yedoma Carbon Stocks). We acknowledge the support by the European Research Council (Starting Grant #338335), the German Federal Ministry of Education and Research (Grant 01DM12011 and "CarboPerm" (03G0836A)), the Initiative and Networking Fund of the Helmholtz Association (#ERC-0013) and the German Federal Environment Agency (UBA, project UFOPLAN FKZ 3712 41 106).

Description: These datasets describe samples taken from yedoma and thermokarst deposits in Baldwin Peninsula (BAL), West-Alaska. Five locations were sampled: a yedoma exposure (B2), three drained thermokarst lake basin (DTLB) exposures (B2, B3 and B4) and a thermokarst lake (UPL1-L1). The collection and analysis of the samples are described in Jongejans et al. (in review). The first four datasets include sampling dates, type of environment (active layer, permafrost or thermokarst lake), site coordinates and the depth from the sediment surface. Dataset https://doi.pangaea.de/10.1594/PANGAEA.892306 presents sedimentological (ice content, bulk density, grain size) and biogeochemical parameters (TC, TN, TOC, C/N, d13C) of the yedoma (B2), DTLB (B3, B4 and B5) and thermokarst lake (UPL1-L1) sediments. Dataset https://doi.pangaea.de/10.1594/PANGAEA.892307 presents the radiocarbon ages (with standard deviation ±) from chosen samples taken from the yedoma (B2), DTLB (B4) and thermokarst lake (UPL1-L1) sediments. Calibrated and rounded calibrated ages are presented. Calibrations were performed according to Stuiver et al. (2017) using CALIB 7.1 software and the IntCal13 calibration curve. Dataset https://doi.pangaea.de/10.1594/PANGAEA.892308 presents n-alkane data from the yedoma (B2) and DTLB (B4) sediments. Concentrations per n-alkane, as well as total n-alkane concentration are presented. Also, two indices (CPI and ACL) are presented that were calculated from the n-alkane concentration. Dataset https://doi.pangaea.de/10.1594/PANGAEA.892309 presents GDGT data from the yedoma (B2) and DTLB (B4) sediments. Concentrations per structure, as well as total brGDGT and crenarchaeol concentrations are presented.

Description: Abundances (percent cover, counts or biomass) of rocky mid-intertidal macro-species measured through a multi-factorial in situ experiment of 14 months in 2012-2013 in Sainte-Flavie, Québec, Canada (48°37'42.5″ N, 68°11'55.7″ W). Using 0.25-m² plots, we ran an in situ one-pulse experiment (removal of all materials to bare rock and then burning of the surface) followed by a full orthogonal factorial design of three press-type disturbances or stresses: grazer reduction, canopy removal, and nutrient enrichment. We evaluated percentage cover visually. Counts and biomass were obtained destructively at the end of the experiment. For further details, refer to our paper (https://doi.org/10.1002/ecs2.2467).

Description: This data set includes the data for the publication Fuchs et al. (2019), Organic carbon and nitrogen stocks along a thermokarst lake sequence in Arctic Alaska, doi:10.1029/2018JG004591. Impacts of successive thermokarst lake stages on soil organic carbon and nitrogen storage, Arctic Alaska. This study combines terrestrial and lacustrine cores to a depth of two meters for a carbon and nitrogen stock estimation in a heavily thermokarst affected study region as well as describes the landscape chronology of the study area which is characterized by multiple drained thermokarst lake basins of different generations. The first data set (doi:10.1594/PANGAEA.895163) includes the raw laboratory data (TOC, TC, TN, C/N) from the permafrost cores collected at the Teshekpuk Lake Area. The data for the lacustrine cores are published on Pangaea and accessible with the link: https://doi.org/10.1594/PANGAEA.864814 (Lenz et al., 2016). All laboratory analyses on the terrestrial cores were carried out at the Alfred Wegener Institute Potsdam. The second data set (doi:10.1594/PANGAEA.895165) presents the carbon (in kg C m-2) and nitrogen (in kg N m-2) stocks for all the collected cores for the reference depths 0-30 cm, 0-100 cm, 0-150 cm, 0-200 cm. This includes terrestrial as well as lacustrine cores. The third data set (doi:10.1594/PANGAEA.895166) includes 19 radiocarbon dates from five different permafrost cores. The samples were analyzed at the Radiocarbon Laboratory in Poznan, Poland with the accelerated mass spectrometry (AMS) dating method (Goslar et al., 2004). In addition to the AMS dates, the radiocarbon dates were calibrated with the Calib 7.1 software into calibrated years before present and organic carbon accumulation rates were calculated for each of the cores (Stuiver & Reimer, 1993; Stuiver et al., 2017). In addition, a shapefile (Landforms_Teshekpuk_Area) is available including drained thermokarst lake basins of different lake stages, thermokarst lakes (〉1 ha), primary surfaces and drainage channels. This landform classification was used in the original study to characterize the chronology of the landscape as well as to calculate landscape carbon and nitrogen stocks.

Description: These data are laboratory results for carbon characteristics (TOC, TC, TN, C/N ratio, stable carbon isotope ratio, radiocarbon ages from bulk organic material), sediment characteristics (mass specific magnetic susceptibility (4.65 kHz & 0.465 kHz), grain size measurements 〈 1 mm) and ice characteristics (sample mass (wet), sample mass (dry), absolute ice content, stable oxygen and hydrogen isotope ratios of pore ice, pH and conductivity of pore ice). Two cores were analyzed: Yedoma core YED1 N 61.75967° / E 130.47438°; h = 218 m asl total length: 22,35 m (recovery 21,13 m) ice wedge included from ~7,14 to ~9,5 m Alas core Alas1 drilled in the drained part of a thermokarst lake basin N 61.76490° / E 130.46503° total length: 19,80 m (recovery 11,14 m) unfrozen conditions from ~1,6 to ~7,5 m Both cores were drilled in March 2015 from dry land surface in a joint expedition of the ERC PETA-Carb poject and the DFG project UL426/1-1 "Short and long-term thermokarst dynamics due to climate changes and human impacts in Central Yakutia, Siberia (2013-2016)". The sample names are compiled as [campaign]-[core] [drive] [depth (top)] - [depth (bottom)]. Age calibration was done with Calib7.10. Grain size percentages were calculated using GRADISTAT (Blott and Pye, 2001). Missing carbon isotope and C/N ratio values are a result of carbon and/or nitrogen contents below detection limit (0.1 wt%). Missing ice characteristics values are a result of dry and/or fine material obstructing the pore ice/water extraction.