{"type": "FeatureCollection", "features": [{"id": "10.5281/zenodo.14185189", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:22:15Z", "type": "Dataset", "title": "Dataset: experiments on volatile organic compounds uptake by the active layer soils of Greenlandic permafrost areas", "description": "This dataset is associated with a publication currently under peer review (DOI and link to the publication will be updated upon its publication). Permafrost serves as a significant carbon reservoir, storing up to 1700 petagrams of carbon accumulated over millennia. As global warming accelerates permafrost thaw, this carbon can be mobilized, with a fraction being transformed into volatile organic compounds (VOCs). These VOCs can influence atmospheric oxidizing capacity and contribute to the formation of secondary organic aerosols. In this study, active layer soils\u2014the seasonally unfrozen layer above the permafrost\u2014were collected from two contrasting Greenlandic permafrost locations (Disko Island, and Kangerlussuaq) and incubated to investigate their role in soil-atmosphere VOC exchange. Laboratory incubations were conducted under controlled conditions, where a VOC mixture gas was continuously purged through jars containing the soil samples. Gas concentrations were monitored at the inlet and outlet using a PTR-ToF-MS, allowing for the estimation of VOC uptake rates based on the differences in VOC concentrations. The results demonstrated that these soils actively function as VOC sinks, despite variations in their physicochemical properties. Soils from upper active layers showed relatively higher uptake capacities, with soil moisture, organic matter, and microbial carbon content identified as key factors influencing uptake rates. Additionally, uptake coefficients for several major VOC species were calculated, providing valuable data for future model development. Correlation analysis and varying uptake coefficients suggest that the sink is likely biotic, with selective preferences for different VOCs.\u00a0The findings indicate that the development of a deeper active layer under climate change could enhance the soil\u2019s sink capacity and mitigate net VOC emissions from permafrost thaw. Detailed methods and interpretations of the results can be found in the associated publication.", "keywords": ["volatile organic compounds", "Disko Island", "active layer", "sink", "Kangerlussuaq", "permafrost"], "contacts": [{"organization": "Jiao, Yi, Kramsh\u00f8j, Magnus, Davie-Martin, Cleo, Elberling, Bo, Rinnan, Riikka,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.14185189"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.14185189", "name": "item", "description": "10.5281/zenodo.14185189", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.14185189"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2024-11-19T00:00:00Z"}}, {"id": "10.1002/2017GB005693", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:13:58Z", "type": "Journal Article", "created": "2017-10-02", "title": "Release of Black Carbon From Thawing Permafrost Estimated by Sequestration Fluxes in the East Siberian Arctic Shelf Recipient", "description": "Abstract

Black carbon (BC) plays an important role in carbon burial in marine sediments globally. Yet the sequestration of BC in the Arctic Ocean is poorly understood. Here we assess the concentrations, fluxes, and sources of soot BC (SBC)\uffe2\uff80\uff94the most refractory component of BC\uffe2\uff80\uff94in sediments from the East Siberian Arctic Shelf (ESAS), the World's largest shelf sea system. SBC concentrations in the contemporary shelf sediments range from 0.1 to 2.1\uffc2\uffa0mg\uffc2\uffa0g\uffe2\uff88\uff921\uffc2\uffa0dw, corresponding to 2\uffe2\uff80\uff9312% of total organic carbon. The 210Pb\uffe2\uff80\uff90derived fluxes of SBC (0.42\uffe2\uff80\uff9311\uffc2\uffa0g\uffc2\uffa0m\uffe2\uff88\uff922\uffc2\uffa0yr\uffe2\uff88\uff921) are higher or in the same range as fluxes reported for marine surface sediments closer to anthropogenic emissions. The total burial flux of SBC in the ESAS (~4,000\uffc2\uffa0Gg\uffc2\uffa0yr\uffe2\uff88\uff921) illustrates the great importance of this Arctic shelf in marine sequestration of SBC. The radiocarbon signal of the SBC shows more depleted yet also more uniform signatures (\uffe2\uff88\uff92721 to \uffe2\uff88\uff92896\uffe2\uff80\uffb0; average of \uffe2\uff88\uff92774\uffc2\uffa0\uffc2\uffb1\uffc2\uffa062\uffe2\uff80\uffb0) than of the non\uffe2\uff80\uff90SBC pool (\uffe2\uff88\uff92304 to \uffe2\uff88\uff92728\uffe2\uff80\uffb0; average of \uffe2\uff88\uff92491\uffc2\uffa0\uffc2\uffb1\uffc2\uffa0163\uffe2\uff80\uffb0), suggesting that SBC is coming from an, on average, 5,900\uffc2\uffa0\uffc2\uffb1\uffc2\uffa0300\uffc2\uffa0years older and more specific source than the non\uffe2\uff80\uff90SBC pool. We estimate that the atmospheric BC input to the ESAS is negligible (~0.6% of the SBC burial flux). Statistical source apportionment modeling suggests that the ESAS sedimentary SBC is remobilized by thawing of two permafrost carbon (PF/C) systems: surface soil permafrost (topsoil/PF; 25\uffc2\uffa0\uffc2\uffb1\uffc2\uffa08%) and Pleistocene ice complex deposits (ICD/PF; 75\uffc2\uffa0\uffc2\uffb1\uffc2\uffa08%). The SBC contribution to the total mobilized permafrost carbon (PF/C) increases with increasing distance from the coast (from 5 to 14%), indicating that the SBC is more recalcitrant than other forms of translocated PF/C. These results elucidate for the first time the key role of permafrost thaw in the transport of SBC to the Arctic Ocean. With ongoing global warming, these findings have implications for the biogeochemical carbon cycle, increasing the size of this refractory carbon pool in the Arctic Ocean.

", "keywords": ["13. Climate action", "Arctic Ocean", "SDG 14 - Life Below Water", "14. Life underwater", "black carbon", "01 natural sciences", "permafrost", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017GB005693"}, {"href": "https://doi.org/10.1002/2017GB005693"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Biogeochemical%20Cycles", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1002/2017GB005693", "name": "item", "description": "10.1002/2017GB005693", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1002/2017GB005693"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2017-10-01T00:00:00Z"}}, {"id": "10.1002/2017gb005693", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:13:59Z", "type": "Journal Article", "created": "2017-10-02", "title": "Release of Black Carbon From Thawing Permafrost Estimated by Sequestration Fluxes in the East Siberian Arctic Shelf Recipient", "description": "Abstract

Black carbon (BC) plays an important role in carbon burial in marine sediments globally. Yet the sequestration of BC in the Arctic Ocean is poorly understood. Here we assess the concentrations, fluxes, and sources of soot BC (SBC)\uffe2\uff80\uff94the most refractory component of BC\uffe2\uff80\uff94in sediments from the East Siberian Arctic Shelf (ESAS), the World's largest shelf sea system. SBC concentrations in the contemporary shelf sediments range from 0.1 to 2.1\uffc2\uffa0mg\uffc2\uffa0g\uffe2\uff88\uff921\uffc2\uffa0dw, corresponding to 2\uffe2\uff80\uff9312% of total organic carbon. The 210Pb\uffe2\uff80\uff90derived fluxes of SBC (0.42\uffe2\uff80\uff9311\uffc2\uffa0g\uffc2\uffa0m\uffe2\uff88\uff922\uffc2\uffa0yr\uffe2\uff88\uff921) are higher or in the same range as fluxes reported for marine surface sediments closer to anthropogenic emissions. The total burial flux of SBC in the ESAS (~4,000\uffc2\uffa0Gg\uffc2\uffa0yr\uffe2\uff88\uff921) illustrates the great importance of this Arctic shelf in marine sequestration of SBC. The radiocarbon signal of the SBC shows more depleted yet also more uniform signatures (\uffe2\uff88\uff92721 to \uffe2\uff88\uff92896\uffe2\uff80\uffb0; average of \uffe2\uff88\uff92774\uffc2\uffa0\uffc2\uffb1\uffc2\uffa062\uffe2\uff80\uffb0) than of the non\uffe2\uff80\uff90SBC pool (\uffe2\uff88\uff92304 to \uffe2\uff88\uff92728\uffe2\uff80\uffb0; average of \uffe2\uff88\uff92491\uffc2\uffa0\uffc2\uffb1\uffc2\uffa0163\uffe2\uff80\uffb0), suggesting that SBC is coming from an, on average, 5,900\uffc2\uffa0\uffc2\uffb1\uffc2\uffa0300\uffc2\uffa0years older and more specific source than the non\uffe2\uff80\uff90SBC pool. We estimate that the atmospheric BC input to the ESAS is negligible (~0.6% of the SBC burial flux). Statistical source apportionment modeling suggests that the ESAS sedimentary SBC is remobilized by thawing of two permafrost carbon (PF/C) systems: surface soil permafrost (topsoil/PF; 25\uffc2\uffa0\uffc2\uffb1\uffc2\uffa08%) and Pleistocene ice complex deposits (ICD/PF; 75\uffc2\uffa0\uffc2\uffb1\uffc2\uffa08%). The SBC contribution to the total mobilized permafrost carbon (PF/C) increases with increasing distance from the coast (from 5 to 14%), indicating that the SBC is more recalcitrant than other forms of translocated PF/C. These results elucidate for the first time the key role of permafrost thaw in the transport of SBC to the Arctic Ocean. With ongoing global warming, these findings have implications for the biogeochemical carbon cycle, increasing the size of this refractory carbon pool in the Arctic Ocean.Ongoing and amplified climate change in the Arctic is leading to glacier retreat and to the exposure of an ever\uffe2\uff80\uff90larger portion of non\uffe2\uff80\uff90glaciated permafrost\uffe2\uff80\uff90dominated landscapes. Warming will also cause more precipitation to fall as rain, further enhancing the thaw of previously frozen ground. Yet, the impact of those perturbations on the geochemistry of Arctic rivers remains a subject of debate. Here, we determined the geochemical composition of waters from various contrasting non\uffe2\uff80\uff90glacial permafrost catchments and investigated their impact on a glacially dominated river, the Zackenberg River (Northeast Greenland), during late summer (August 2019). We also studied the effect of rainfall on the geochemistry of the Zackenberg River, its non\uffe2\uff80\uff90glacial tributaries, and a nearby independent non\uffe2\uff80\uff90glacial headwater stream Gr\uffc3\uffa6nse. We analyzed water properties, quantified and characterized dissolved organic matter (DOM) using absorbance and fluorescence spectroscopy and radiocarbon isotopes, and set this alongside analyses of the major cations (Ca, Mg, Na, and K), dissolved silicon (Si), and germanium/silicon ratios (Ge/Si). The glacier\uffe2\uff80\uff90fed Zackenberg River contained low concentrations of major cations, dissolved Si and dissolved organic carbon (DOC), and a Ge/Si ratio typical of bulk rock. Glacial DOM was enriched in protein\uffe2\uff80\uff90like fluorescent DOM and displayed relatively depleted radiocarbon values (i.e., old DOM). Non\uffe2\uff80\uff90glacial streams (i.e., tributaries and Gr\uffc3\uffa6nse) had higher concentrations of major cations and DOC and DOM enriched in aromatic compounds. They showed a wide range of values for radiocarbon, Si and Ge/Si ratios associated with variable contributions of surface runoff relative to deep active layer leaching. Before the rain event, Zackenberg tributaries did not contribute notably to the solute export of the Zackenberg River, and supra\uffe2\uff80\uff90permafrost ground waters governed the supply of solutes in Zackenberg tributaries and Gr\uffc3\uffa6nse stream. After the rain event, surface runoff modified the composition of Gr\uffc3\uffa6nse stream, and non\uffe2\uff80\uff90glacial tributaries strongly increased their contribution to the Zackenberg River solute export. Our results show that summer rainfall events provide an additional source of DOM and Si\uffe2\uff80\uff90rich waters from permafrost\uffe2\uff80\uff90underlain catchments to the discharge of glacially dominated rivers. This suggests that the magnitude and composition of solute exports from Arctic rivers are modulated by permafrost thaw and summer rain events. This event\uffe2\uff80\uff90driven solute supply will likely impact the carbon cycle in rivers, estuaries, and oceans and should be included into future predictions of carbon balance in these vulnerable Arctic systems.The stabilizing properties of mineral\uffe2\uff80\uff93organic carbon (OC) interactions have been studied in many soil environments (temperate soils, podzol lateritic soils, and paddy soils). Recently, interest in their role in permafrost regions is increasing as permafrost was identified as a hotspot of change. In thawing ice\uffe2\uff80\uff90rich permafrost regions, such as the Yedoma domain, 327\uffe2\uff80\uff93466 Gt of frozen OC is buried in deep sediments. Interactions between minerals and OC are important because OC is located very near the mineral matrix. Mineral surfaces and elements could mitigate recent and future greenhouse gas emissions through physical and/or physicochemical protection of OC. The dynamic changes in redox and pH conditions associated with thermokarst lake formation and drainage trigger metal\uffe2\uff80\uff90oxide dissolution and precipitation, likely influencing OC stabilization and microbial mineralization. However, the influence of thermokarst processes on mineral\uffe2\uff80\uff93OC interactions remains poorly constrained. In this study, we aim to characterize Fe, Mn, Al, and Ca minerals and their potential protective role for OC. Total and selective extractions were used to assess the crystalline and amorphous oxides or complexed metal pools as well as the organic acids found within these pools. We analyzed four sediment cores from an ice\uffe2\uff80\uff90rich permafrost area in Central Yakutia, which were drilled (i) in undisturbed Yedoma uplands, (ii) beneath a recent lake formed within Yedoma deposits, (iii) in a drained thermokarst lake basin, and (iv) beneath a mature thermokarst lake from the early Holocene period. We find a decrease in the amount of reactive Fe, Mn, Al, and Ca in the deposits on lake formation (promoting reduction reactions), and this was largely balanced by an increase in the amount of reactive metals in the deposits on lake drainage (promoting oxidation reactions). We demonstrate an increase in the metal to C molar ratio on thermokarst process, which may indicate an increase in metal\uffe2\uff80\uff93C bindings and could provide a higher protective role against microbial mineralization of organic matter. Finally, we find that an increase in mineral\uffe2\uff80\uff93OC interactions corresponded to a decrease in CO2 and CH4 gas emissions on thermokarst process. Mineral\uffe2\uff80\uff93OC interactions could mitigate greenhouse gas production from permafrost thaw as soon as lake drainage occurs.Background and aims: Permafrost degradation has the potential to change the Arctic tundra landscape. We observed rapid local thawing of ice-rich permafrost resulting in thaw pond formation, which was triggered by removal of the shrub cover in a field experiment. This study aimed to examine the rate of permafrost thaw and the initial vegetation succession after the permafrost collapse. Methods: In the experiment, we measured changes in soil thaw depth, plant species cover and soil subsidence over nine years (2007\u20132015). Results: After abrupt initial thaw, soil subsidence in the removal plots continued indicating further thawing of permafrost albeit at a much slower pace: 1 cm y\u22121 over 2012\u20132015 vs. 5 cm y\u22121 over 2007\u20132012. Grass cover strongly increased after the initial shrub removal, but later declined with ponding of water in the subsiding removal plots. Sedges established and expanded in the wetter removal plots. Thereby, the removal plots have become increasingly similar to nearby \u2018natural\u2019 thaw ponds. Conclusions: The nine years of field observations in a unique shrub removal experiment at a Siberian tundra site document possible trajectories of small-scale permafrost collapse and the initial stage of vegetation recovery, which is essential knowledge for assessing future tundra landscape changes.

", "keywords": ["0301 basic medicine", "Ecology (including Biodiversity Conservation)", "Permafrost degradation", "Betula nana", "15. Life on land", "01 natural sciences", "Thermokarst", "Vegetation dynamics", "03 medical and health sciences", "13. Climate action", "Arctic tundra", "Environmental Sciences", "SDG 15 - Life on Land", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://doi.org/10.1007/s11104-017-3369-8"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plant%20and%20Soil", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s11104-017-3369-8", "name": "item", "description": "10.1007/s11104-017-3369-8", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s11104-017-3369-8"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2017-08-22T00:00:00Z"}}, {"id": "10.1029/2020gb006719", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:17:27Z", "type": "Journal Article", "created": "2020-11-18", "title": "Stream Dissolved Organic Matter in Permafrost Regions Shows Surprising Compositional Similarities but Negative Priming and Nutrient Effects", "description": "Abstract

Permafrost degradation is delivering bioavailable dissolved organic matter (DOM) and inorganic nutrients to surface water networks. While these permafrost subsidies represent a small portion of total fluvial DOM and nutrient fluxes, they could influence food webs and net ecosystem carbon balance via priming or nutrient effects that destabilize background DOM. We investigated how addition of biolabile carbon (acetate) and inorganic nutrients (nitrogen and phosphorus) affected DOM decomposition with 28\uffe2\uff80\uff90day incubations. We incubated late\uffe2\uff80\uff90summer stream water from 23 locations nested in seven northern or high\uffe2\uff80\uff90altitude regions in Asia, Europe, and North America. DOM loss ranged from 3% to 52%, showing a variety of longitudinal patterns within stream networks. DOM optical properties varied widely, but DOM showed compositional similarity based on Fourier transform ion cyclotron resonance mass spectrometry (FT\uffe2\uff80\uff90ICR MS) analysis. Addition of acetate and nutrients decreased bulk DOM mineralization (i.e., negative priming), with more negative effects on biodegradable DOM but neutral or positive effects on stable DOM. Unexpectedly, acetate and nutrients triggered breakdown of colored DOM (CDOM), with median decreases of 1.6% in the control and 22% in the amended treatment. Additionally, the uptake of added acetate was strongly limited by nutrient availability across sites. These findings suggest that biolabile DOM and nutrients released from degrading permafrost may decrease background DOM mineralization but alter stoichiometry and light conditions in receiving waterbodies. We conclude that priming and nutrient effects are coupled in northern aquatic ecosystems and that quantifying two\uffe2\uff80\uff90way interactions between DOM properties and environmental conditions could resolve conflicting observations about the drivers of DOM in permafrost zone waterways.

", "keywords": ["0106 biological sciences", "550", "permafrost regions", "thermokarst", "vaikutukset", "ta1171", "geosciences", "ikirouta", "carbon cycling", "551", "ravinteet", "01 natural sciences", "nutrients", "cryosphere and high-latitude processes", "Biology", "Research Articles", "organic matter", "0105 earth and related environmental sciences", "compositional similarities", "nutrients and nutrient cycling", "hiilen kierto", "ravinteiden kierr\u00e4tys", "15. Life on land", "rivers", "6. Clean water", "nutrient effects", "13. Climate action", "orgaaninen aines", "1171 Geotieteet", "SDG 6 - Clean Water and Sanitation", "joet", "permafrost"]}, "links": [{"href": "https://digitalcommons.usu.edu/context/biology_facpub/article/2820/viewcontent/2020GB006719.pdf"}, {"href": "https://doi.org/10.1029/2020gb006719"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Biogeochemical%20Cycles", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1029/2020gb006719", "name": "item", "description": "10.1029/2020gb006719", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1029/2020gb006719"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-01-01T00:00:00Z"}}, {"id": "10.1029/2020gb006672", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:17:27Z", "type": "Journal Article", "created": "2020-09-02", "title": "Assessing the Potential for Mobilization of Old Soil Carbon After Permafrost Thaw: A Synthesis of 14C Measurements From the Northern Permafrost Region", "description": "Abstract

The magnitude of future emissions of greenhouse gases from the northern permafrost region depends crucially on the mineralization of soil organic carbon (SOC) that has accumulated over millennia in these perennially frozen soils. Many recent studies have used radiocarbon (14C) to quantify the release of this \uffe2\uff80\uff9cold\uffe2\uff80\uff9d SOC as CO2 or CH4 to the atmosphere or as dissolved and particulate organic carbon (DOC and POC) to surface waters. We compiled ~1,900 14C measurements from 51 sites in the northern permafrost region to assess the vulnerability of thawing SOC in tundra, forest, peatland, lake, and river ecosystems. We found that growing season soil 14C\uffe2\uff80\uff90CO2 emissions generally had a modern (post\uffe2\uff80\uff901950s) signature, but that well\uffe2\uff80\uff90drained, oxic soils had increased CO2 emissions derived from older sources following recent thaw. The age of CO2 and CH4 emitted from lakes depended primarily on the age and quantity of SOC in sediments and on the mode of emission, and indicated substantial losses of previously frozen SOC from actively expanding thermokarst lakes. Increased fluvial export of aged DOC and POC occurred from sites where permafrost thaw caused soil thermal erosion. There was limited evidence supporting release of previously frozen SOC as CO2, CH4, and DOC from thawing peatlands with anoxic soils. This synthesis thus suggests widespread but not universal release of permafrost SOC following thaw. We show that different definitions of \uffe2\uff80\uff9cold\uffe2\uff80\uff9d sources among studies hamper the comparison of vulnerability of permafrost SOC across ecosystems and disturbances. We also highlight opportunities for future 14C studies in the permafrost region.On\uffe2\uff80\uff90going shrinkage of Greenland's icecap, permafrost thaw, and changes in precipitation are exposing its landscapes to erosion and remobilization of ancient organic carbon (OC) held in soils and sedimentary rocks. The fate of this OC and potential feedbacks to climate are still unclear. Here, we show that the glacial Zackenberg river (Northeastern Greenland) exports aged particulate OC (POC, uncalibrated radiocarbon ages of \uffe2\uff88\uffbc4,000\uffc2\uffa0years). Many of the smaller periglacial streams affected by abrupt permafrost thaw transport substantially older POC (up to 32,000\uffc2\uffa0years), especially with enhanced discharge following intense precipitation. Mineralogical analysis, and density and size fractionation of soils and both glacial and nonglacial river sediments reveal that OC is largely associated with phyllosilicate minerals, suggesting stabilization against microbial processing. Enhanced export of ancient, mineral\uffe2\uff80\uff90associated OC as a consequence of summer rainfall may accelerate translocation of OC from terrestrial to marine environments, but could have limited consequences for climate.Erosion of permafrost coasts due to climate warming releases large quantities of organic carbon (OC) into the Arctic Ocean. While burial of permafrost OC in marine sediments potentially limits degradation, resuspension of sediments in the nearshore zone potentially enhances degradation and greenhouse gas production, adding to the \uffe2\uff80\uff9cpermafrost carbon feedback.\uffe2\uff80\uff9d Recent studies, focusing on bulk sediments, suggest that permafrost OC derived from coastal erosion is predominantly deposited close to shore. However, bulk approaches disregard sorting processes in the coastal zone, which strongly influence the OC distribution and fate. We studied soils and sediments along a transect from the fast\uffe2\uff80\uff90eroding shoreline of Herschel Island\uffe2\uff80\uff94Qikiqtaruk (Yukon, Canada) to a depositional basin offshore. Sample material was fractionated by density (1.8\uffc2\uffa0g\uffc2\uffa0cm\uffe2\uff88\uff923) and size (63\uffc2\uffa0\uffce\uffbcm), separating loose OC from mineral\uffe2\uff80\uff90associated OC. Each fraction was analyzed for element content (TOC, TN), carbon isotopes (\uffce\uffb413C, \uffce\uff9414C), molecular biomarkers (n\uffe2\uff80\uff90alkanes, n\uffe2\uff80\uff90alkanoic acids, lignin phenols, cutin acids), and mineral surface area. The OC partitioning between fractions changes considerably along the transect, highlighting the importance of hydrodynamic sorting in the nearshore zone. Additionally, OC and biomarker loadings decrease along the land\uffe2\uff80\uff90ocean transect, indicating significant loss of OC during transport. However, molecular proxies for degradation show contrasting trends, suggesting that OC losses are not always well reflected in its degradation state. This study, using fraction partitioning that crosses land\uffe2\uff80\uff90ocean boundaries in a way not done before, aids to disentangle sorting processes from degradation patterns, and provides quantitative insight into losses of thawed and eroded permafrost OC.Continental margins receive, process and sequester most of the terrestrial organic carbon (terrOC) released into the ocean. In the Arctic, increasing fluvial discharge and collapsing permafrost are expected to enhance terrOC release and degradation, leading to ocean acidification and translocated CO2 release to the atmosphere. However, the processes controlling terrOC transport beyond the continental shelf, and the amount of terrOC that reaches the slope and the rise are poorly described. Here we study terrOC transport to the Laptev Sea continental slope and rise by probing surface sediments with dual\uffe2\uff80\uff90isotope (\uffce\uffb413C/\uffce\uff9414C) source apportionment, degradation\uffe2\uff80\uff90diagnostic terrestrial biomarkers (n\uffe2\uff80\uff90alkanes, n\uffe2\uff80\uff90alkanoic acids, lignin phenols) and 210Pbxs\uffe2\uff80\uff90based mass accumulation rates (MAR). The MAR\uffe2\uff80\uff90terrOC (g\uffc2\uffa0m\uffe2\uff88\uff922\uffc2\uffa0yr\uffe2\uff88\uff921) decrease from 14.7\uffc2\uffa0\uffc2\uffb1\uffc2\uffa012.2 on the shelf, to 7.0\uffc2\uffa0\uffc2\uffb1\uffc2\uffa05.8 over the slope, to 2.3\uffc2\uffa0\uffc2\uffb1\uffc2\uffa00.3 for the rise. Scaling this to the respective regimes yields that 80% of the terrOC accumulates on the shelf, while 11% and 9% of the accumulation occurs in slope and rise sediments, respectively. TerrOC remineralization is evidenced by biomarker degradation proxies (CPI of n\uffe2\uff80\uff90alkanes and 3,5Bd/V) indicating 40% and 60% more terrOC degradation from slope to rise, consistent with a decline in terrOC concentrations by 57%. TerrOC degradation only partially explains this decline. An updated Laptev Sea terrOC budget suggests that sediment transport dynamics such as turbidity currents may drive terrOC shelf\uffe2\uff80\uff90basin export, contributing to the observed accumulation pattern. This study quantitatively demonstrates that Arctic shelf seas are key receptor systems for remobilized terrOC, emphasizing their importance in the carbon cycle of the rapidly changing Arctic.The abrupt warming events punctuating the Termination 1 (about 11.7\uffe2\uff80\uff9318\uffc2\uffa0ka Before Present, BP) were marked by sharp rises in the concentration of atmospheric methane (CH4). The role of permafrost organic carbon (OC) in these rises is still debated, with studies based on top\uffe2\uff80\uff90down measurements of radiocarbon (14C) content of CH4 trapped in ice cores suggesting minimum contributions from old and strongly 14C\uffe2\uff80\uff90depleted permafrost OC. However, organic matter from permafrost can exhibit a continuum of 14C ages (contemporaneous to >50\uffc2\uffa0ky). Here, we investigate the large\uffe2\uff80\uff90scale permafrost remobilization at the Younger Dryas\uffe2\uff80\uff90Preboreal transition (ca. 11.6\uffc2\uffa0ka BP) using the sedimentary record deposited at the Lena River paleo\uffe2\uff80\uff90outlet (Arctic Ocean) to reflect permafrost destabilization in this vast drainage basin. Terrestrial OC was isolated from sediments and characterized geochemically measuring \uffce\uffb413C, \uffce\uff9414C, and lignin phenol molecular fossils. Results indicate massive remobilization of relatively young (about 2,600\uffc2\uffa0years) permafrost OC from inland Siberia after abrupt warming triggered severe active layer deepening. Methane emissions from this young fraction of permafrost OC contributed to the deglacial CH4 rise. This study stresses that underestimating permafrost complexities may affect our comprehension of the deglacial permafrost OC\uffe2\uff80\uff90climate feedback and helps understand how modern permafrost systems may react to rapid warming events, including enhanced CH4 emissions that would amplify anthropogenic climate change.Ongoing permafrost thaw in the Arctic may remobilize large amounts of old organic matter. Upon transport to the Siberian shelf seas, this material may be degraded and released to the atmosphere, exported off\uffe2\uff80\uff90shelf, or buried in the sediments. While our understanding of the fate of permafrost\uffe2\uff80\uff90derived organic matter in shelf waters is improving, poor constraints remain regarding degradation in sediments. Here we use an extensive data set of organic carbon concentrations and isotopes (n\uffc2\uffa0=\uffc2\uffa0109) to inventory terrigenous organic carbon (terrOC) in surficial sediments of the Laptev and East Siberian Seas (LS\uffc2\uffa0+\uffc2\uffa0ESS). Of these ~2.7 Tg terrOC about 55% appear resistant to degradation on a millennial timescale. A first\uffe2\uff80\uff90order degradation rate constant of 1.5\uffc2\uffa0kyr\uffe2\uff88\uff921 is derived by combining a previously established relationship between water depth and cross\uffe2\uff80\uff90shelf sediment\uffe2\uff80\uff90terrOC transport time with mineral\uffe2\uff80\uff90associated terrOC loadings. This yields a terrOC degradation flux of ~1.7\uffc2\uffa0Gg/year from surficial sediments during cross\uffe2\uff80\uff90shelf transport, which is orders of magnitude lower than earlier estimates for degradation fluxes of dissolved and particulate terrOC in the water column of the LS\uffc2\uffa0+\uffc2\uffa0ESS. The difference is mainly due to the low degradation rate constant of sedimentary terrOC, likely caused by a combination of factors: (i) the lower availability of oxygen in the sediments compared to fully oxygenated waters, (ii) the stabilizing role of terrOC\uffe2\uff80\uff90mineral associations, and (iii) the higher proportion of material that is intrinsically recalcitrant due to its chemical/molecular structure in sediments. Sequestration of permafrost\uffe2\uff80\uff90released terrOC in shelf sediments may thereby attenuate the otherwise expected permafrost carbon\uffe2\uff80\uff90climate feedback.Climate warming is expected to destabilize permafrost carbon (PF\uffe2\uff80\uff90C) by thaw\uffe2\uff80\uff90erosion and deepening of the seasonally thawed active layer and thereby promote PF\uffe2\uff80\uff90C mineralization to CO2 and CH4. A similar PF\uffe2\uff80\uff90C remobilization might have contributed to the increase in atmospheric CO2 during deglacial warming after the last glacial maximum. Using carbon isotopes and terrestrial biomarkers (\uffce\uff9414C, \uffce\uffb413C, and lignin phenols), this study quantifies deposition of terrestrial carbon originating from permafrost in sediments from the Chukchi Sea (core SWERUS\uffe2\uff80\uff90L2\uffe2\uff80\uff904\uffe2\uff80\uff90PC1). The sediment core reconstructs remobilization of permafrost carbon during the late Aller\uffc3\uffb8d warm period starting at 13,000\uffc2\uffa0cal\uffc2\uffa0years before present (BP), the Younger Dryas, and the early Holocene warming until 11,000\uffc2\uffa0cal\uffc2\uffa0years BP and compares this period with the late Holocene, from 3,650\uffc2\uffa0years BP until present. Dual\uffe2\uff80\uff90carbon\uffe2\uff80\uff90isotope\uffe2\uff80\uff90based source apportionment demonstrates that Ice Complex Deposit\uffe2\uff80\uff94ice\uffe2\uff80\uff90 and carbon\uffe2\uff80\uff90rich permafrost from the late Pleistocene (also referred to as Yedoma)\uffe2\uff80\uff94was the dominant source of organic carbon (66\uffc2\uffa0\uffc2\uffb1\uffc2\uffa08%; mean\uffc2\uffa0\uffc2\uffb1\uffc2\uffa0standard deviation) to sediments during the end of the deglaciation, with fluxes more than twice as high (8.0\uffc2\uffa0\uffc2\uffb1\uffc2\uffa04.6\uffc2\uffa0g\uffc2\uffb7m\uffe2\uff88\uff922\uffc2\uffb7year\uffe2\uff88\uff921) as in the late Holocene (3.1\uffc2\uffa0\uffc2\uffb1\uffc2\uffa01.0\uffc2\uffa0g\uffc2\uffb7m\uffe2\uff88\uff922\uffc2\uffb7year\uffe2\uff88\uff921). These results are consistent with late deglacial PF\uffe2\uff80\uff90C remobilization observed in a Laptev Sea record, yet in contrast with PF\uffe2\uff80\uff90C sources, which at that location were dominated by active layer material from the Lena River watershed. Release of dormant PF\uffe2\uff80\uff90C from erosion of coastal permafrost during the end of the last deglaciation indicates vulnerability of Ice Complex Deposit in response to future warming and sea level changes.Ongoing rapid arctic warming leads to extensive permafrost thaw, which in turn increases the hydrologic connectivity of the landscape by opening up subsurface flow paths. Suspended particulate organic matter (POM) has proven useful to trace permafrost thaw signals in arctic rivers, which may experience higher organic matter loads in the future due to expansion and increasing intensity of thaw processes such as thermokarst and river bank erosion. Here we focus on the Kolyma River watershed in Northeast Siberia, the world's largest watershed entirely underlain by continuous permafrost. To evaluate and characterize the present\uffe2\uff80\uff90day fluvial release of POM from permafrost thaw, we collected water samples every 4\uffe2\uff80\uff937 days during the 4\uffe2\uff80\uff90month open water season in 2013 and 2015 from the lower Kolyma River mainstem and from a small nearby headwater stream (Y3) draining an area completely underlain by Yedoma permafrost (Pleistocene ice\uffe2\uff80\uff90 and organic\uffe2\uff80\uff90rich deposits). Concentrations of particulate organic carbon generally followed the hydrograph with the highest concentrations during the spring flood in late May/early June. For the Kolyma River, concentrations of dissolved organic carbon showed a similar behavior, in contrast to the headwater stream, where dissolved organic carbon values were generally higher and particulate organic carbon concentrations lower than for Kolyma. Carbon isotope analysis (\uffce\uffb413C, \uffce\uff9414C) suggested Kolyma\uffe2\uff80\uff90POM to stem from both contemporary and older permafrost sources, while Y3\uffe2\uff80\uff90POM was more strongly influenced by in\uffe2\uff80\uff90stream production and recent vegetation. Lipid biomarker concentrations (high\uffe2\uff80\uff90molecular\uffe2\uff80\uff90weight n\uffe2\uff80\uff90alkanoic acids and n\uffe2\uff80\uff90alkanes) did not display clear seasonal patterns, yet implied Y3\uffe2\uff80\uff90POM to be more degraded than Kolyma\uffe2\uff80\uff90POM.Collapse of permafrost coasts delivers large quantities of particulate organic carbon (POC) to Arctic coastal areas. With rapidly changing environmental conditions, sediment and organic carbon (OC) mobilization and transport pathways are also changing. Here, we assess the sources and sinks of POC in the highly dynamic nearshore zone of Herschel Island\uffe2\uff80\uff90Qikiqtaruk (Yukon, Canada). Our results show that POC concentrations sharply decrease, from 15.9 to 0.3\uffc2\uffa0mg\uffc2\uffa0L\uffe2\uff88\uff921, within the first 100\uffe2\uff80\uff93300\uffc2\uffa0m offshore. Simultaneously, radiocarbon ages of POC drop from 16,400 to 3,600 14C years, indicating rapid settling of old permafrost POC to underlying sediments. This suggests that permafrost OC is, apart from a very narrow resuspension zone (<5\uffc2\uffa0m water depth), predominantly deposited in nearshore sediments. While long\uffe2\uff80\uff90term storage of permafrost OC in marine sediments potentially limits biodegradation and its subsequent release as greenhouse gas, resuspension of fine\uffe2\uff80\uff90grained, OC\uffe2\uff80\uff90rich sediments in the nearshore zone potentially enhances OC turnover.The burial of terrestrial organic carbon (terrOC) in marine sediments contributes to the regulation of atmospheric CO2 on geological timescales and may mitigate positive feedback to present-day climate warming. However, the fate of terrOC in marine settings is debated, with uncertainties regarding its degradation during transport. Here, we employ compound-specific radiocarbon analyses of terrestrial biomarkers to determine cross-shelf transport times. For the World\uffe2\uff80\uff99s largest marginal sea, the East Siberian Arctic shelf, transport requires 3600\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff89300 years for the 600\uffe2\uff80\uff89km from the Lena River to the Laptev Sea shelf edge. TerrOC was reduced by ~85% during transit resulting in a degradation rate constant of 2.4\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.6\uffe2\uff80\uff89kyr\uffe2\uff88\uff921. Hence, terrOC degradation during cross-shelf transport constitutes a carbon source to the atmosphere over millennial time. For the contemporary carbon cycle on the other hand, slow terrOC degradation brings considerable attenuation of the decadal-centennial permafrost carbon-climate feedback caused by global warming.Warming in the Arctic accelerates thawing of permafrost-affected soils, which leads to a release of greenhouse gases to the atmosphere. We do not know whether permafrost thaw also releases non-methane volatile organic compounds that can contribute to both negative and positive radiative forcing on climate. Here we show using proton transfer reaction\uffe2\uff80\uff93time of flight\uffe2\uff80\uff93mass spectrometry that substantial amounts of ethanol and methanol and in total 316 organic ions were released from Greenlandic permafrost soils upon thaw in laboratory incubations. We demonstrate that the majority of this release is taken up in the active layer above. In an experiment using 14C-labeled ethanol and methanol, we demonstrate that these compounds are consumed by microorganisms. Our findings highlight that the thawing permafrost soils are not only a considerable source of volatile organic compounds but also that the active layer regulates their release into the atmosphere.

", "keywords": ["0301 basic medicine", "Ethanol", "Science", "Climate", "Methanol", "General Biochemistry", "Genetics and Molecular Biology", "Q", "General Physics and Astronomy", "Permafrost", "General Chemistry", "15. Life on land", "01 natural sciences", "Article", "03 medical and health sciences", "13. Climate action", "11. Sustainability", "SDG 13 - Climate Action", "Soil Microbiology", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://www.nature.com/articles/s41467-018-05824-y.pdf"}, {"href": "https://doi.org/10.1038/s41467-018-05824-y"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Nature%20Communications", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1038/s41467-018-05824-y", "name": "item", "description": "10.1038/s41467-018-05824-y", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1038/s41467-018-05824-y"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2018-08-24T00:00:00Z"}}, {"id": "10.1038/s41467-022-31540-9", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:17:34Z", "type": "Journal Article", "created": "2022-07-01", "title": "Global stocks and capacity of mineral-associated soil organic carbon", "description": "Abstract

Soil is the largest terrestrial reservoir of organic carbon and is central for climate change mitigation and carbon-climate feedbacks. Chemical and physical associations of soil carbon with minerals play a critical role in carbon storage, but the amount and global capacity for storage in this form remain unquantified. Here, we produce spatially-resolved global estimates of mineral-associated organic carbon stocks and carbon-storage capacity by analyzing 1144 globally-distributed soil profiles. We show that current stocks total 899 Pg C to a depth of 1\uffe2\uff80\uff89m in non-permafrost mineral soils. Although this constitutes 66% and 70% of soil carbon in surface and deeper layers, respectively, it is only 42% and 21% of the mineralogical capacity. Regions under agricultural management and deeper soil layers show the largest undersaturation of mineral-associated carbon. Critically, the degree of undersaturation indicates sequestration efficiency over years to decades. We show that, across 103 carbon-accrual measurements spanning management interventions globally, soils furthest from their mineralogical capacity are more effective at accruing carbon; sequestration rates average 3-times higher in soils at one tenth of their capacity compared to soils at one half of their capacity. Our findings provide insights into the world\uffe2\uff80\uff99s soils, their capacity to store carbon, and priority regions and actions for soil carbon management.Subsea permafrost represents a large carbon pool that might be or become a significant greenhouse gas source. Scarcity of observational data causes large uncertainties. We here use five 21-56\uffe2\uff80\uff89m long subsea permafrost cores from the Laptev Sea to constrain organic carbon (OC) storage and sources, degradation state and potential greenhouse gas production upon thaw. Grain sizes, optically-stimulated luminescence and biomarkers suggest deposition of aeolian silt and fluvial sand over 160 000 years, with dominant fluvial/alluvial deposition of forest- and tundra-derived organic matter. We estimate an annual thaw rate of 1.3\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.6\uffe2\uff80\uff89kg OC m\uffe2\uff88\uff922 in subsea permafrost in the area, nine-fold exceeding organic carbon thaw rates for terrestrial permafrost. During 20-month incubations, CH4 and CO2 production averaged 1.7 nmol and 2.4 \uffc2\uffb5mol g\uffe2\uff88\uff921 OC d\uffe2\uff88\uff921, providing a baseline to assess the contribution of subsea permafrost to the high CH4 fluxes and strong ocean acidification observed in the region.Arctic change is expected to destabilize terrestrial carbon (terrOC) in soils and permafrost, leading to fluvial release, greenhouse gas emission and climate feedback. However, landscape heterogeneity and location-specific observations complicate large-scale assessments of terrOC mobilization. Here we reveal differences in terrOC release, deduced from the Circum-Arctic Sediment Carbon Database (CASCADE) using source-diagnostic (\uffce\uffb413C-\uffce\uff9414C) and carbon accumulation data. The results show five-times larger terrOC release from the Eurasian than from the American Arctic. Most of the circum-Arctic terrOC originates from near-surface soils (61%); 30% stems from Pleistocene-age permafrost. TerrOC translocation, relative to land-based terrOC stocks, varies by a factor of five between circum-Arctic regions. Shelf seas with higher relative terrOC translocation follow the spatial pattern of recent Arctic warming, while such with lower translocation reflect long-distance lateral transport with efficient remineralization of terrOC. This study provides a receptor-based perspective for how terrOC release varies across the circum-Arctic.Recent hypotheses, based on atmospheric records and models, suggest that permafrost carbon (PF-C) accumulated during the last glaciation may have been an important source for the atmospheric CO2 rise during post-glacial warming. However, direct physical indications for such PF-C release have so far been absent. Here we use the Laptev Sea (Arctic Ocean) as an archive to investigate PF-C destabilization during the last glacial\uffe2\uff80\uff93interglacial period. Our results show evidence for massive supply of PF-C from Siberian soils as a result of severe active layer deepening in response to the warming. Thawing of PF-C must also have brought about an enhanced organic matter respiration and, thus, these findings suggest that PF-C may indeed have been an important source of CO2 across the extensive permafrost domain. The results challenge current paradigms on the post-glacial CO2 rise and, at the same time, serve as a harbinger for possible consequences of the present-day warming of PF-C soils.Volatile organic compounds (VOCs) play an essential role in climate change and air pollution by modulating tropospheric oxidation capacity and providing precursors for ozone and aerosol formation. Arctic permafrost buries large quantities of frozen soil carbon, which could be released as VOCs with permafrost thawing or collapsing as a consequence of global warming. However, due to the lack of reported studies in this field and the limited capability of the conventional measurement techniques, it is poorly understood how much VOCs could be emitted from thawing permafrost and the chemical speciation of the released VOCs. Here we apply a Vocus proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF) in laboratory incubations for the first time to examine the release of VOCs from thawing permafrost peatland soils sampled from Finnish Lapland. The warming-induced rapid VOC emissions from the thawing soils were mainly attributed to the direct release of old, trapped gases from the permafrost. The average VOC fluxes from thawing permafrost were four times as high as those from the active layer (the top layer of soil in permafrost terrain). The emissions of less volatile compounds, i.e. sesquiterpenes and diterpenes, increased substantially with rising temperatures. Results in this study demonstrate the potential for substantive VOC releases from thawing permafrost. We anticipate that future global warming could stimulate VOC emissions from the Arctic permafrost, which may significantly influence the Arctic atmospheric chemistry and climate change.The permafrost active layer is a key supplier of soil organic carbon and mineral nutrients to Arctic rivers. In the active layer, sites of soil-water exchange are locations for organic carbon and nutrient mobilization. Previously these sites were considered as connected during summer months and isolated during winter months. Whether soil pore waters in active layer soils are connected during shoulder seasons is poorly understood. In this study, exceptionally heavy silicon isotope compositions in soil pore waters show that during late winter, there is no connection between isolated pockets of soil pore water in soils with a shallow active layer. However, lighter silicon isotope compositions in soil pore waters reveal that soils are biogeochemically connected for longer than previously considered in soils with a deeper active layer. We show that an additional 21% of the 0\uffe2\uff80\uff931\uffe2\uff80\uff89m soil organic carbon stock is exposed to soil - water exchange. This marks a hot moment during a dormant season, and an engine for organic carbon transport from active layer soils. Our findings mark the starting point to locate earlier pathways for biogeochemical connectivity, which need to be urgently monitored to quantify the seasonal flux of organic carbon released from permafrost soils.Vast amounts of carbon are bound in both active layer and permafrost soils in the Arctic. As a consequence of climate warming, the depth of the active layer is increasing in size and permafrost soils are thawing. We hypothesize that pulses of biogenic volatile organic compounds are released from the near\uffe2\uff80\uff90surface active layer during spring, and during late summer season from thawing permafrost, while the subsequent biogeochemical processes occurring in thawed soils also lead to emissions. Biogenic volatile organic compounds are reactive gases that have both negative and positive climate forcing impacts when introduced to the Arctic atmosphere, and the knowledge of their emission magnitude and pattern is necessary to construct reliable climate models. However, it is unclear how different ecosystems and environmental factors such as drainage conditions upon permafrost thaw affect the emission and compound composition. Here we show that incubations of frozen B horizon of the active layer and permafrost soils collected from a High Arctic heath and fen release a range of biogenic volatile organic compounds upon thaw and during subsequent incubation experiments at temperatures of 10\uffc2\uffb0C and 20\uffc2\uffb0C. Meltwater drainage in the fen soils increased emission rates nine times, while having no effect in the drier heath soils. Emissions generally increased with temperature, and emission profiles for the fen soils were dominated by benzenoids and alkanes, while benzenoids, ketones, and alcohols dominated in heath soils. Our results emphasize that future changes affecting the drainage conditions of the Arctic tundra will have a large influence on volatile emissions from thawing permafrost soils \uffe2\uff80\uff93 particularly in wetland/fen areas.

", "keywords": ["0301 basic medicine", "tundra", "Climate Change", "Permafrost", "01 natural sciences", "meltwater drainage", "Soil", "03 medical and health sciences", "Arctic", "11. Sustainability", "biogenic volatile organic compounds", "gas fluxes", "Tundra", "0105 earth and related environmental sciences", "Volatile Organic Compounds", "Arctic Regions", "Water", "15. Life on land", "soil ecology", "climate change", "13. Climate action", "Gases", "Seasons", "permafrost", "Environmental Monitoring"]}, "links": [{"href": "https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcb.14582"}, {"href": "https://doi.org/10.1111/gcb.14582"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Change%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/gcb.14582", "name": "item", "description": "10.1111/gcb.14582", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/gcb.14582"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-02-25T00:00:00Z"}}, {"id": "10.1073/pnas.2019672118", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:17:54Z", "type": "Journal Article", "created": "2021-03-01", "title": "Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf", "description": "Significance

Extensive release of methane from sediments of the world\uffe2\uff80\uff99s largest continental shelf, the East Siberian Arctic Ocean (ESAO), is one of the few Earth system processes that can cause a net transfer of carbon from land/ocean to the atmosphere and thus amplify global warming on the timescale of this century. An important gap in our current knowledge concerns the contributions of different subsea pools to the observed methane releases. This knowledge is a prerequisite to robust predictions on how these releases will develop in the future. Triple-isotope\uffe2\uff80\uff93based fingerprinting of the origin of the highly elevated ESAO methane levels points to a limited contribution from shallow microbial sources and instead a dominating contribution from a deep thermogenic pool.Rapid Arctic warming is accelerating permafrost thaw and mobilizing previously frozen organic carbon (OC) into waterways. Upon thaw, permafrost\uffe2\uff80\uff90derived OC can become susceptible to microbial degradation that may lead to greenhouse gas emissions (GHG), thus accelerating climate change. Abrupt permafrost thaw (e.g., riverbank erosion, retrogressive thaw slumps) occurs in areas rich in OC. Given the high OC content and the increase in frequency of abrupt thaw events, these environments may increasingly contribute to permafrost GHG emissions in the future. To better assess these emissions from abrupt permafrost thaw, we incubated thaw stream waters from an abrupt permafrost thaw site (Duvanny Yar, Siberia) and additionally, waters from their outflow to the Kolyma River. Our results show that CO2 release by volume from thaw streams was substantially higher than CO2 emissions from the river outflow waters, while the opposite was true for CO2 release normalized to the suspended sediment weight (gram dry weight). The CH4 emissions from both thaw streams and outflow waters were at a similar range, but an order of magnitude lower than those of CO2. Additionally, we show that nearshore riverbank waters differ in their biogeochemistry from thaw streams and Kolyma River mainstem: particles resemble thaw streams while dissolved fraction is more alike to the Kolyma River thalweg. In these waters dissolved OC losses are faster than in the river thalweg. Our incubations offer a first insight into the GHG release from permafrost thaw streams that connect exposed and degrading permafrost outcrops to larger river systems.Major Arctic rivers are undergoing changes due to climate warming with higher discharge and increased amounts of solutes and organic carbon (OC) draining into rivers and coastal seas. Permafrost thaw mobilizes previously frozen OC to the fluvial network where it can be degraded into greenhouse gases and emitted to the atmosphere. Degradation of OC during downstream transport, especially of the particulate OC (POC), is however poorly characterized. Here, we quantified POC degradation in the Kolyma River, the largest river system underlain with continuous permafrost, during 9\uffe2\uff80\uff9315 d whole-water incubations (containing POC and dissolved OC\uffe2\uff80\uff94DOC) during two seasons: spring freshet (early June) and late summer (end of July). Furthermore, we examined interactions between dissolved and particulate phases using parallel incubations of filtered water (only DOC). We measured OC concentrations and carbon isotopes (\uffce\uffb413C, \uffce\uff9414C) to define carbon losses and to characterize OC composition, respectively. We found that both POC composition and biodegradability differs greatly between seasons. During summer, POC was predominantly autochthonous (47%\uffe2\uff80\uff9395%) and degraded rapidly (\uffe2\uff88\uffbc33% loss) whereas freshet POC was largely of allochthonous origin (77%\uffe2\uff80\uff9396%) and less degradable. Gains in POC concentrations (up to 31%) were observed in freshet waters that could be attributed to flocculation and adsorption of DOC to particles. The demonstrated DOC flocculation and adsorption to POC indicates that the fate and dynamics of the substantially-sized DOC pool may shift from degradation to settling, depending on season and POC concentrations\uffe2\uff80\uff94the latter potentially acting to attenuate greenhouse gas emissions from fluvial systems. We finally note that DOC incubations without POC present may yield degradation estimates that do not reflect degradation in the in situ river conditions, and that interaction between dissolved and particulate phases may be important to consider when determining fluvial carbon dynamics and feedbacks under a changing climate.In Arctic regions, thawing permafrost soils are projected to release 50 to 250 Gt of carbon by 2100. This data is mostly derived from carbon\uffe2\uff80\uff90rich wetlands, although 71% of this carbon pool is stored in faster\uffe2\uff80\uff90thawing mineral soils, where ecosystems close to the outer boundaries of permafrost regions are especially vulnerable. Although extensive data exists from currently thawing sites and short\uffe2\uff80\uff90term thawing experiments, investigations of the long\uffe2\uff80\uff90term changes following final thaw and co\uffe2\uff80\uff90occurring drainage are scarce. Here we show ecosystem changes at two comparable tussock tundra sites with distinct permafrost thaw histories, representing 15 and 25\uffc2\uffa0years of natural drainage, that resulted in a 10\uffe2\uff80\uff90fold decrease in CH4 emissions (3.2\uffc2\uffa0\uffc2\uffb1\uffc2\uffa02.2 vs. 0.3\uffc2\uffa0\uffc2\uffb1\uffc2\uffa00.4\uffc2\uffa0mg C\uffe2\uff80\uff90CH4\uffc2\uffa0m\uffe2\uff88\uff922\uffc2\uffa0day\uffe2\uff88\uff921), while CO2 emissions were comparable. These data extend the time perspective from earlier studies based on short\uffe2\uff80\uff90term experimental drainage. The overall microbial community structures did not differ significantly between sites, although the drier top soils at the most advanced site led to a loss of methanogens and their syntrophic partners in surface layers while the abundance of methanotrophs remained unchanged. The resulting deeper aeration zones likely increased CH4 oxidation due to the longer residence time of CH4 in the oxidation zone, while the observed loss of aerenchyma plants reduced CH4 diffusion from deeper soil layers directly to the atmosphere. Our findings highlight the importance of including hydrological, vegetation and microbial specific responses when studying long\uffe2\uff80\uff90term effects of climate change on CH4 emissions and underscores the need for data from different soil types and thaw histories.Climate warming can result in both abiotic (e.g., permafrost thaw) and biotic (e.g., microbial functional genes) changes in Arctic tundra. Recent research has incorporated dynamic permafrost thaw in Earth system models (ESMs) and indicates that Arctic tundra could be a significant future carbon (C) source due to the enhanced decomposition of thawed deep soil C. However, warming\uffe2\uff80\uff90induced biotic changes may influence biologically related parameters and the consequent projections inESMs. How model parameters associated with biotic responses will change under warming and to what extent these changes affect projected C budgets have not been carefully examined. In this study, we synthesized six data sets over 5\uffc2\uffa0years from a soil warming experiment at the Eight Mile Lake, Alaska, into the TerrestrialECOsystem (TECO) model with a probabilistic inversion approach. TheTECOmodel used multiple soil layers to track dynamics of thawed soil under different treatments. Our results show that warming increased light use efficiency of vegetation photosynthesis but decreased baseline (i.e., environment\uffe2\uff80\uff90corrected) turnover rates ofSOCin both the fast and slow pools in comparison with those under control. Moreover, the parameter changes generally amplified over time, suggesting processes of gradual physiological acclimation and functional gene shifts of both plants and microbes. TheTECOmodel predicted that field warming from 2009 to 2013 resulted in cumulative C losses of 224 or 87\uffc2\uffa0g/m2, respectively, without or with changes in those parameters. Thus, warming\uffe2\uff80\uff90induced parameter changes reduced predicted soil C loss by 61%. Our study suggests that it is critical to incorporate biotic changes inESMs to improve the model performance in predicting C dynamics in permafrost regions.

", "keywords": ["550", "Climate Change", "Permafrost", "acclimation", "carbon modeling", "01 natural sciences", "climate warming", "Soil", "Theoretical", "Models", "soil carbon", "Photosynthesis", "biotic responses", "data assimilation", "Tundra", "Soil Microbiology", "0105 earth and related environmental sciences", "Ecology", "500", "Biological Sciences", "Models", " Theoretical", "Plants", "15. Life on land", "Carbon", "Climate Action", "Environmental sciences", "Biological sciences", "Earth sciences", "13. Climate action", "Environmental Sciences", "Alaska", "permafrost"]}, "links": [{"href": "https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcb.14325"}, {"href": "https://doi.org/10.1111/gcb.14325"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Change%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/gcb.14325", "name": "item", "description": "10.1111/gcb.14325", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/gcb.14325"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2018-06-12T00:00:00Z"}}, {"id": "10.1111/gcb.16394", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:18:32Z", "type": "Journal Article", "created": "2022-08-17", "title": "Lowering water table reduces carbon sink strength and carbon stocks in northern peatlands", "description": "Abstract

Peatlands at high latitudes have accumulated >400\uffe2\uff80\uff89Pg carbon (C) because saturated soil and cold temperatures suppress C decomposition. This substantial amount of C in Arctic and Boreal peatlands is potentially subject to increased decomposition if the water table (WT) decreases due to climate change, including permafrost thaw\uffe2\uff80\uff90related drying. Here, we optimize a version of the Organizing Carbon and Hydrology In Dynamic Ecosystems model (ORCHIDEE\uffe2\uff80\uff90PCH4) using site\uffe2\uff80\uff90specific observations to investigate changes in CO2 and CH4 fluxes as well as C stock responses to an experimentally manipulated decrease of WT at six northern peatlands. The unmanipulated control peatlands, with the WT <20\uffe2\uff80\uff89cm on average (seasonal max up to 45\uffe2\uff80\uff89cm) below the surface, currently act as C sinks in most years (58\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff8934\uffe2\uff80\uff89g C\uffe2\uff80\uff89m\uffe2\uff88\uff922\uffc2\uffa0year\uffe2\uff88\uff921; including 6\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff897\uffe2\uff80\uff89g C\uffe2\uff80\uff93CH4 m\uffe2\uff88\uff922\uffc2\uffa0year\uffe2\uff88\uff921 emission). We found, however, that lowering the WT by 10\uffe2\uff80\uff89cm reduced the CO2 sink by 13\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff8915\uffe2\uff80\uff89g\uffe2\uff80\uff89C\uffe2\uff80\uff89m\uffe2\uff88\uff922\uffc2\uffa0year\uffe2\uff88\uff921 and decreased CH4 emission by 4\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff894\uffe2\uff80\uff89g CH4 m\uffe2\uff88\uff922\uffc2\uffa0year\uffe2\uff88\uff921, thus accumulating less C over 100\uffe2\uff80\uff89years (0.2\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.2\uffe2\uff80\uff89kg\uffe2\uff80\uff89C\uffe2\uff80\uff89m\uffe2\uff88\uff922). Yet, the reduced emission of CH4, which has a larger greenhouse warming potential, resulted in a net decrease in greenhouse gas balance by 310\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff89360\uffe2\uff80\uff89g\uffe2\uff80\uff89CO2\uffe2\uff80\uff90eq\uffc2\uffa0m\uffe2\uff88\uff922\uffc2\uffa0year\uffe2\uff88\uff921. Peatlands with the initial WT close to the soil surface were more vulnerable to C loss: Non\uffe2\uff80\uff90permafrost peatlands lost >2\uffe2\uff80\uff89kg\uffe2\uff80\uff89C\uffe2\uff80\uff89m\uffe2\uff88\uff922 over 100\uffe2\uff80\uff89years when WT is lowered by 50\uffe2\uff80\uff89cm, while permafrost peatlands temporally switched from C sinks to sources. These results highlight that reductions in C storage capacity in response to drying of northern peatlands are offset in part by reduced CH4 emissions, thus slightly reducing the positive carbon climate feedbacks of peatlands under a warmer and drier future climate scenario.

Permafrost soils, which store almost half of the global belowground organic carbon (OC), are susceptible to thaw upon climate warming. On the Peel Plateau of northwestern Canada, the number and size of retrogressive thaw slumps (RTS) has increased in recent decades due to rising temperatures and higher precipitation. These RTS features caused by the rapid thaw of ice-rich permafrost release organic matter dominantly as particulate organic carbon (POC) to the stream network. In this study, we sampled POC and streambank sediments along a fluvial transect (\u223c12 km) downstream from two RTS features and assessed the composition and degradation status of the mobilized permafrost OC. We found that RTS features add old, Pleistocene-aged permafrost POC to the stream system that is traceable kilometers downstream. The POC released consists mainly of recalcitrant compounds that persists within stream networks, whereas labile compounds originate from the active layer and appear to largely degrade within the scar zone of the RTS feature. Thermokarst on the Peel Plateau is likely to intensify in the future, but our data suggest that most of the permafrost OC released is not readily degradable within the stream system and thus may have little potential for atmospheric evasion. Possibilities for the recalcitrant OC to degrade over decadal to millennial time scales while being transported via larger river networks, and within the marine environment, do however, still exist. These findings add to our understanding of the vulnerable Arctic landscapes and how they may interact with the global climate.

", "keywords": ["pyrolysis-GCMS", "organic carbon", "Science", "carbon", "Q", "15. Life on land", "01 natural sciences", "Arctic", "13. Climate action", "Arctic; climate; carbon; lipid biomarkers; Peel Plateau; permafrost; pyrolysis-GCMS; degradation", "Peel Plateau", "SDG 13 - Climate Action", "lipid biomarkers", "14. Life underwater", "climate", "permafrost", "degradation", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://doi.org/10.3389/feart.2021.642675"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Frontiers%20in%20Earth%20Science", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3389/feart.2021.642675", "name": "item", "description": "10.3389/feart.2021.642675", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3389/feart.2021.642675"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-03-29T00:00:00Z"}}, {"id": "10.3389/feart.2021.660333", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:20:28Z", "type": "Journal Article", "created": "2021-03-12", "title": "Editorial: Novel Isotope Systems and Biogeochemical Cycling During Cryospheric Weathering in Polar Environments", "description": "Cryospheric weathering processes in permafrost and glaciated environments play an essential role in carbon cycling within the Earth system. Chemical weathering of silicate, carbonate and sulfidebearing rocks releases cations and anions that can consume (or release) atmospheric carbon dioxide (CO2), as well as biologically important nutrients such as phosphorous, iron and silicon, which can impact downstream ecosystems (Figure 1). How these cryospheric weathering processes will respond to future climate-driven changes in permafrost thaw and glacial melt is difficult to predict due to the role of complex forcing mechanisms and feedbacks. Isotope geochemistry utilizes changes in the relative abundance of different isotopes due to physical, chemical and biological reactions, allowing some of the complexities of cryospheric weathering processes to be unpicked. In recent years, there has been an explosion in the range of stable and radiogenic isotope systems used for the study of high-latitude environments, including isotopes of major elements such as carbon, oxygen, and silicon (e.g., Opfergelt et al., 2013; Kutscher et al., 2017), and trace metal isotopes such as strontium (Hindshaw et al., 2014), lithium (Murphy et al., 2019), iron (Zhang et al., 2015), uranium-series (e.g., Arendt et al., 2018) and rare earth elements (e.g., Clinger et al., 2016). This research topic explores some of the developments in high-latitude field and experimental studies that utilize such geochemical tools to trace the degree and nature of weathering reactions that play a critical role in carbon cycling. The nine contributions to the research topic involve the analysis of traditional (C, N, S, O) and non-traditional (Mg, Li, Si, Ge) isotopes from different samples types such as river waters, lake waters, rocks, sediments, or mineral separates from locations both in the Northern (Greenland, Iceland, Canada, Svalbard) and Southern Hemisphere (Patagonia, Antarctica). Two papers use isotope geochemistry to explore organic and inorganic carbon cycling within permafrost and active layer soils. Jones et al. show that biogeochemical processes and decomposition pathways of organic carbon in ice-wedge polygons in Svalbard are dependent upon water and organic carbon content. Sulfur (\u03b434S) and oxygen (\u03b418O) isotopes show that iron and sulfate reduction processes dominate in water saturated, high organic carbon environments, whereas sulfide oxidation dominates in drier areas with less organic carbon. Zolkos and Tank use an experimental approach in combination with stable carbon isotopes (\u03b413CO2) to show that carbonate weathering coupled with sulfide oxidation in recently or previously unthawed Canadian permafrost sediments is a net source of inorganic CO2 to the atmosphere, albeit partly counterbalanced by carbonate buffering.", "keywords": ["glacier", "550", "Science", "Q", "551", "cryosphere", "01 natural sciences", "7. Clean energy", "13. Climate action", "14. Life underwater", "isotope", "permafrost", "geochemistry", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://doi.org/10.3389/feart.2021.660333"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Frontiers%20in%20Earth%20Science", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3389/feart.2021.660333", "name": "item", "description": "10.3389/feart.2021.660333", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3389/feart.2021.660333"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-03-11T00:00:00Z"}}, {"id": "10.3389/feart.2021.703339", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:20:29Z", "type": "Journal Article", "created": "2021-07-23", "title": "Iron Redistribution Upon Thermokarst Processes in the Yedoma Domain", "description": "

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 (R2 = 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.

Abstract. Arctic rivers will be increasingly affected by the hydrological and biogeochemical consequences of thawing permafrost. During transport, permafrost-derived organic carbon (OC) can either accumulate in floodplain and shelf sediments or be degraded into greenhouse gases prior to final burial. Thus, the net impact of permafrost OC on climate will ultimately depend on the interplay of complex processes that occur along the source-to-sink system. Here, we focus on the Kolyma River, the largest watershed completely underlain by continuous permafrost, and marine sediments of the East Siberian Sea, as a transect to investigate the fate of permafrost OC along the land\u2013ocean continuum. Three pools of riverine OC were investigated for the Kolyma main stem and five of its tributaries: dissolved OC (DOC), suspended particulate OC (POC), and riverbed sediment OC (SOC). They were compared with earlier findings in marine sediments. Carbon isotopes (\u03b413C, \u039414C), lignin phenol, and lipid biomarker proxies show a contrasting composition and degradation state of these different carbon pools. Dual C isotope source apportionment calculations imply that old permafrost-OC is mostly associated with sediments (SOC; contribution of 68\u00b110\u2009%), and less dominant in POC (38\u00b18\u2009%), whereas autochthonous primary production contributes around 44\u00b110\u2009% to POC in the main stem and up to 79\u00b111\u2009% in tributaries. Biomarker degradation indices suggest that Kolyma DOC might be relatively degraded, regardless of its generally young age shown by previous studies. In contrast, SOC shows the lowest \u039414C value (oldest OC), yet relatively fresh compositional signatures. Furthermore, decreasing mineral surface area-normalised OC- and biomarker loadings suggest that SOC might be reactive along the land\u2013ocean continuum and almost all parameters were subjected to rapid change when moving from freshwater to the marine environment. This suggests that sedimentary dynamics play a crucial role when targeting permafrost-derived OC in aquatic systems and support earlier studies highlighting the fact that the land\u2013ocean transition zone is an efficient reactor and a dynamic environment. The prevailing inconsistencies between freshwater and marine research (i.e.\u00a0targeting predominantly DOC and SOC respectively) need to be better aligned in order to determine to what degree thawed permafrost OC may be destined for long-term burial, thereby attenuating further global warming.

", "keywords": ["QE1-996.5", "Ecology", "Permafrost", " Climate Feedback", " Climate Change", " Arctic", "Geology", "15. Life on land", "01 natural sciences", "6. Clean water", "Life", "13. Climate action", "QH501-531", "SDG 13 - Climate Action", "14. Life underwater", "QH540-549.5", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://bg.copernicus.org/articles/20/271/2023/bg-20-271-2023.pdf"}, {"href": "https://doi.org/10.5194/bg-20-271-2023"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Biogeosciences", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.5194/bg-20-271-2023", "name": "item", "description": "10.5194/bg-20-271-2023", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5194/bg-20-271-2023"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-06-27T00:00:00Z"}}, {"id": "10.34894/XK4LSU", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:20:56Z", "type": "Dataset", "title": "Porewater \u03b413CDOC Indicates Variable Extent Of Degradation In Different Talik Layers Of Coastal Alaskan Thermokarst Lakes", "description": "The data set includes the results of geochemical and sediment analyses on 7 sediment cores (63.2 cm - 86.5 cm) from two northern Alaskan thermokarst lakes (Emaiksoun and Unnamed Lake). The analysis include lake depth measurements, linescan imaging, XRF scans, grainsize distribution, loss on ignition, porewater content, magnetic susceptibility, dissolved organic carbon concentration, sediment density, stable carbon isotope measurements dissolved organic carbon and soil organic carbon and radiocarbon ages.", "keywords": ["Earth and Environmental Science", "13. Climate action", "Earth and Environmental Sciences", "Thermokarst Lake", "Dissolved Organic Carbon", "Permafrost", "15. Life on land", "Environmental Research", "Natural Sciences", "Geosciences", "Alaska"], "contacts": [{"organization": "Meisel, Ove", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.34894/XK4LSU"}, {"rel": "self", "type": "application/geo+json", "title": "10.34894/XK4LSU", "name": "item", "description": "10.34894/XK4LSU", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.34894/XK4LSU"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-01-01T00:00:00Z"}}, {"id": "10.3389/feart.2020.00229", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-23T16:20:28Z", "type": "Journal Article", "created": "2020-06-26", "title": "Silicon Isotopes Reveal a Non-glacial Source of Silicon to Crescent Stream, McMurdo Dry Valleys, Antarctica", "description": "In high latitude environments, silicon is supplied to river waters by both glacial and non-glacial chemical weathering. The signal of these two end-members is often obscured by biological uptake and/or groundwater input in the river catchment. McMurdo Dry Valleys streams in Antarctica have no deep groundwater input, no connectivity between streams and no surface vegetation cover, and thus provide a simplified system for us to constrain the supply of dissolved silicon (DSi) to rivers from chemical weathering in a glacial environment. Here we report dissolved Si concentrations, germanium/silicon ratios (Ge/Si) and silicon isotope compositions (\u03b430SiDSi) in Crescent Stream, McMurdo Dry Valleys for samples collected between December and February in the 2014\u22122015, 2015\u22122016, and 2016\u22122017 austral seasons. The \u03b430SiDSi compositions and DSi concentrations are higher than values reported in wet-based glacial meltwaters, and form a narrow cluster within the range of values reported for permafrost dominated Arctic Rivers. High \u03b430SiDSi compositions, ranging from +0.90\u2030 to +1.39\u2030, are attributed to (i) the precipitation of amorphous silica during freezing of waters in isolated pockets of the hyporheic zone in the winter and the release of Si from unfrozen pockets during meltwater-hyporheic zone exchange in the austral summer, and (ii) additional Si isotope fractionation via long-term Si uptake in clay minerals and seasonal Si uptake into diatoms superimposed on this winter-derived isotope signal. There is no relationship between \u03b430SiDSi compositions and DSi concentrations with seasonal and daily discharge, showing that stream waters contain DSi that is in equilibrium with the formation of secondary Si minerals in the hyporheic zone. We show that \u03b430SiDSi compositions can be used as tracers of silicate weathering in the hyporheic zone and possible tracers of freeze-thaw conditions in the hyporheic zone. This is important in the context of the ongoing warming in McMurdo Dry Valleys and the supply of more meltwaters to the hyporheic zone of McMurdo Dry Valley streams.", "keywords": ["550", "Science", "Q", "silicon", "Antartica", "15. Life on land", "551", "01 natural sciences", "hyporheic zone", "silicon isotopes", "13. Climate action", "weathering", "Antarctica", "isotopes", "permafrost", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://doi.org/10.3389/feart.2020.00229"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Frontiers%20in%20Earth%20Science", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3389/feart.2020.00229", "name": "item", "description": "10.3389/feart.2020.00229", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3389/feart.2020.00229"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-06-26T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=PERMAFROST&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=PERMAFROST&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=PERMAFROST&", "hreflang": "en-US"}, {"rel": "next", "type": "application/geo+json", "title": "items (next)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=PERMAFROST&offset=50", "hreflang": "en-US"}], "numberMatched": 133, "numberReturned": 50, "distributedFeatures": [], "timeStamp": "2026-05-25T03:59:58.526636Z"}