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Global warming can substantially affect the export of dissolved organic carbon (DOC) from peat-permafrost to aquatic systems. The direct degradability of such peat-derived DOC, however, is poorly constrained because previous permafrost thaw studies have mainly addressed mineral soil catchments or DOC pools that have already been processed in surface waters. We incubated peat cores from a palsa mire to compare an active layer and an experimentally thawed permafrost layer with regard to DOC composition and degradation potentials of pore water DOC. Our results show that DOC from the thawed permafrost layer had high initial degradation potentials compared with DOC from the active layer. In fact, the DOC that showed the highest bio- and photo-degradability, respectively, originated in the thawed permafrost layer. Our study sheds new light on the DOC composition of peat-permafrost directly upon thaw and suggests that past estimates of carbon-dioxide emissions from thawed peat permafrost may be biased as they have overlooked the initial mineralization potential of the exported DOC.
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http://dx.doi.org/10.1038/srep45811 | DOI Listing |
Proc Natl Acad Sci U S A
September 2025
Colorado State University, Department of Forest and Rangeland Stewardship, Fort Collins, CO 80523.
The streams of Alaska's Brooks Range lie within a vast (~14M ha) tract of protected wilderness and have long supported both resident and anadromous fish. However, dozens of historically clear streams have recently turned orange and turbid. Thawing permafrost is thought to have exposed sulfide minerals to weathering, delivering iron and other potentially toxic metals to aquatic ecosystems.
View Article and Find Full Text PDFEnviron Sci Technol
September 2025
Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2R3, Canada.
Permafrost thaw in peatlands risks increasing the production and mobilization of methylmercury (MeHg), a bioaccumulative neurotoxin that poses a health hazard to humans. We studied 12 peatlands on a trophic gradient in northwestern Canada, including permafrost peat plateaus and thawed bogs and fens, to determine the effects of thaw on MeHg production from measures of soil and porewater MeHg and in situ methylation assays. The production of MeHg was greater in thawed peatlands, especially rich fens, as indicated by higher potential rates of microbial methylation of inorganic mercury (Hg) to MeHg and higher soil %MeHg (MeHg:total Hg).
View Article and Find Full Text PDFSci Data
August 2025
Permafrost Research Section, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 14473, Potsdam, Germany.
Retrogressive Thaw Slumps (RTS) are widespread mass-wasting hillslope failures triggered by thawing permafrost. While regional studies have provided insights into the spatial distribution and dynamics of RTS, a consistent and unbiased quantification and monitoring remains unsolved at pan-arctic scales. We present the Database of AI-detected Arctic RTS footprints (DARTS), comprising ~43,000 individual footprints of active RTS or active areas within larger RTS landforms.
View Article and Find Full Text PDFNat Commun
August 2025
State Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou, 730000, China.
The world's largest continuous alpine permafrost layer on the Tibet Plateau (TP), is increasingly threatened by warming leading permafrost degradation that disrupts carbon, water, and nutrient cycling, and threatens ecosystem services and infrastructure stability. However, it remains unclear how permafrost sensitivity to warming varies across the TP and over time. By compiling a 20-year (2001-2020) dataset from 55 in situ monitoring sites, we find permafrost thawing rates increased from 45 ± 15 cm·10a (2001-2010) to 86 ± 30 cm·10a (2011-2020), while the temperature increasing rates at the top of permafrost rose from 0.
View Article and Find Full Text PDFNat Commun
August 2025
State Key Laboratory of Forage Breeding-by-Design and Utilization; Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Methane (CH) emissions from thawing permafrost could amplify climate warming. However, long-term trajectory of net CH balance in permafrost regions, particularly high-altitude permafrost regions, remains unknown. Based on literature synthesis and CLM5.
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