Changes in hydrological regime regulate POC export across permafrost-dominated Arctic River basins

Abstract

Warming-driven acceleration of hydrological processes is altering the carbon cycle in permafrost-dominated Arctic regions, yet the underlying drivers remain unclear. This study analyzes ArcticGRO data (2003-2021) from six major Arctic rivers (Ob, Yenisei, Lena, Kolyma, Yukon, and Mackenzie) to investigate trends and spatial-temporal variations in riverine particulate organic carbon (POC). The annual POC flux from these six rivers, estimated using the Load Estimator (LOADEST), averaged 2.78 Tg. Only the Lena River showed a notable annual decrease in POC flux ( − 3.9%/yr, p < 0.001) and concentration ( − 12%/yr, p < 0.001), while the Yukon River exhibited increasing streamflow (+0.98%/yr, p < 0.001) and POC flux (+3.2%/yr, p < 0.001). POC flux variations were primarily governed by streamflow and POC concentration, with higher concentrations in spring floods period and lower during winter. Spatial differences were linked to drainage density ( Dd ) and forest coverage ( Fc ). The Yukon River basin, with a higher Dd of 0.2 km/km ² and lower Fc approximately 24%, exhibits the highest POC concentrations (2.3 mg/L). In contrast, the Yenisei River basin has the lowest POC concentration ( ∼ 0.4 mg/L), along with a relatively low drainage density ( Dd = 0.18 km/km ² ) and a high forest cover ( Fc = 67%). Permafrost conditions constrained riverine POC export, with isotopic evidence indicating a shift from a carbon sink to a source, as POC carbon age increased by ∼ 200 to 1700 years (4%-68%) annually, peaking in winter (700-2500 years) after 2012. Rivers with lower permafrost coverage (e.g., Ob, Yenisei), exhibit higher winter POC fluxes contributions (10%-20%), while others contributed < 5%, suggesting the role of permafrost degradation in winter carbon export. This study emphasizes the need to assess climate-driven hydrological shifts and permafrost thaw in shaping Arctic land-to-ocean carbon fluxes.

Keywords

Particulate organic carbon / Arctic rivers / Permafrost degradation / Climate change / Hydrological regime

CRediT authorship contribution statement

Shiqi Liu: Writing - original draft, Software, Investigation, Data curation. Ping Wang: Writing - review & editing, Project administration, Conceptualization. Jingjie Yu: Writing - review & editing, Supervision, Project administration, Conceptualization. Renjie Zhou: Writing - review & editing. Bing Bai: Visualization. Olga I. Gabysheva: Writing - review & editing. Natalia L. Frolova: Writing - review & editing. Sergey P. Pozdniakov: Writing - review & editing.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This research was funded by the National Natural Science Foundation of China (Nos. 42371033, W2412055), the Science & Technology Fundamental Resources Investigation Program (Nos. 2022FY101901-3), Russian Science Foundation (No. 25-47-00056) and the state assignment of the Ministry of Science and Higher Education of the Russian Federation (No. AAAA-A21-121012190036-6). We sincerely thank the Arctic Great Rivers Observatory (ArcticGRO) for providing river basin boundaries, daily discharge data, and water quality data (available at https://arcticgreatrivers.org/data/).

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.gsf.2025.102208.

References

[1] Asmala, E., Bowers, D.G., Autio, R., Kaartokallio, H., Thomas, D.N., 2014. Qualitative changes of riverine dissolved organic matter at low salinities due to flocculation. J. Geophys. Res.: Biogeosci. 119 (10), 1919-1933.

[2] Attermeyer, K., Catalán, N., Einarsdottir, K., Freixa, A., Groeneveld, M., Hawkes, J.A., Bergquist, J., Tranvik, L.J., 2018. Organic carbon processing during transport through Boreal Inland Waters: particles as important sites. J. Geophys. Res.: Biogeosci. 123 (8), 2412-2428.

[3] Battin, T.J., Luyssaert, S., Kaplan, L.A., Aufdenkampe, A.K., Richter, A., Tranvik, L.J., 2009. The boundless carbon cycle. Nat. Geosci. 2 (9), 598-600.

[4] Beel, C.R., Heslop, J.K., Orwin, J.F., Pope, M.A., Schevers, A.J., Hung, J.K.Y., Lafrenière, M.J., Lamoureux, S.F., 2021. Emerging dominance of summer rainfall driving High Arctic terrestrial-aquatic connectivity. Nat. Commun. 12 (1), 1448.

[5] Beel, C.R., Lamoureux, S.F., Orwin, J.F., Pope, M.A., Lafrenière, M.J., Scott, N.A., 2020. Differential impact of thermal and physical permafrost disturbances on High Arctic dissolved and particulate fluvial fluxes. Sci. Rep. 10 (1), 11836.

[6] Behnke, M.I., Fellman, J.B., Nagorski, S., Spencer, R.G.M., Hood, E., 2023a. The role of glacier erosion in riverine particulate organic carbon export. Global Biogeochem. Cycles 37 (11), e2023GB 007721.

[7] Behnke, M.I., Tank, S.E., McClelland, J.W., Holmes, R.M., Haghipour, N., Eglinton, T.I., Raymond, P.A., Suslova, A., Zhulidov, A.V., Gurtovaya, T., Zimov, N., Zimov, S., Mutter, E.A., Amos, E., Spencer, R.G.M., 2023b. Aquatic biomass is a major source to particulate organic matter export in large Arctic rivers. Proc. Nat. Acad. Sci. 120 (12), e 2209883120.

[8] Blair, N.E., Aller, R.C., 2012. The fate of terrestrial organic carbon in the marine environment. Annu. Rev. Mar. Science 4, 401-423.

[9] Borrelli, P., Robinson, D., Fleischer, L., Lugato, E., Ballabio, C., Alewell, C., Meusburger, K., Modugno, S., Schütt, B., Ferro, V., Bagarello, V., Oost, K., Montanarella, L., Panagos, P., 2017. An assessment of the global impact of 21st century land use change on soil erosion. Nat. Commun. 8, 1-13.

[10] Bröder, L., Davydova, A., Davydov, S., Zimov, N., Haghipour, N., Eglinton, T.I., Vonk, J. E., 2020. Particulate organic matter dynamics in a permafrost headwater stream and the Kolyma River mainstem. J. Geophys. Res.: Biogeosci. 125 (2), e2019JG 005511.

[11] Brown, D.R.N., Brinkman, T.J., Bolton, W.R., Brown, C.L., Cold, H.S., Hollingsworth, T. N., Verbyla, D.L., 2020. Implications of climate variability and changing seasonal hydrology for subarctic riverbank erosion. Clim. Change 162 (2), 1-20.

[12] Brown, J., Ferrians, O., Heginbottom, J., Melnikov, E., 2002. Circum-Arctic Map of Permafrost and Ground-ice Conditions, Version 2. Boulder. NSIDC, National Snow and Ice Data Center, Colorado, USA.

[13] Campeau, A., Soerensen, A.L., Martma, T., Åkerblom, S., Zdanowicz, C., 2020. Controls on the 14C content of dissolved and particulate organic carbon mobilized across the Mackenzie River Basin, Canada. Global Biogeochem. Cycles 34 (12), 1-15.

[14] Carrie, J., Sanei, H., Goodarzi, F., Stern, G., Wang, F., 2009. Characterization of organic matter in surface sediments of the Mackenzie River Basin, Canada. Int. J. Coal Geol. 77 (3), 416-423.

[15] Chaplot, V., Mutema, M., 2021. Sources and main controls of dissolved organic and inorganic carbon in river basins: a worldwide meta-analysis. J. Hydrol. 603, 126941.

[16] Chen, S.-A., Michaelides, K., Singer, M., Richards, D., 2021. Global analysis of short- versus long-term drainage basin erosion rates. American Geophysical Union, Fall Meeting 2019, abstract #EP53F-2218.

[17] Clark, J.B., Mannino, A., Tzortziou, M., Spencer, R.G.M., Hernes, P., 2022. The transformation and export of organic carbon across an Arctic River-Delta-Ocean continuum. J. Geophys. Res.: Biogeosci. 127 (12), e2022JG 007139.

[18] Coppola, A.I., Wiedemeier, D.B., Galy, V., Haghipour, N., Hanke, U.M., Nascimento, G. S., Usman, M., Blattmann, T.M., Reisser, M., Freymond, C.V., Zhao, M., Voss, B., Wacker, L., Schefuß E., Peucker-Ehrenbrink, B., Abiven, S., Schmidt, M.W.I., Eglinton, T.I., 2018. Global-scale evidence for the refractory nature of riverine black carbon. Nat. Geosci. 11 (8), 584-588.

[19] Cudowski, A., Pietryczuk, A., Hauschild, T., 2015. Aquatic fungi in relation to the physical and chemical parameters of water quality in the Augustów Canal. Fungal Ecol. 13, 193-204.

[20] Dai, M., Yin, Z., Meng, F., Liu, Q., Cai, W.-J., 2012. Spatial distribution of riverine DOC inputs to the ocean: an updated global synthesis. Curr. Opin. Environ. Sustain. 4 (2), 170-178.

[21] Dickens, A., Baldock, J., Kenna, T., Eglinton, T., 2011. A depositional history of particulate organic carbon in a floodplain lake from the lower Ob’ River, Siberia. Geochim. Cosmochim. Acta 75, 4796-4815.

[22] Dragićević N., Karleuša, B., Oz̆anić N., 2019. Different approaches to estimation of drainage density and their effect on the erosion potential method. Water 11 (3), 593.

[23] Eppes, M.C., Magi, B., Scheff, J., Warren, K., Ching, S., Feng, T., 2020. Warmer, wetter climates accelerate mechanical weathering in field data, independent of stress-loading. Geophys. Res. Lett. 47 (24), 2020GL 089062.

[24] Fabre, C., Sauvage, S., Probst, J.L., Sánchez-Pérez, J.M., 2020. Global-scale daily riverine DOC fluxes from lands to the oceans with a generic model. Global Planet. Change 194, 103294.

[25] Fabre, C., Sauvage, S., Tananaev, N., Noel, G.E., Teisserenc, R., Probst, J.L., Perez, J.M.S., 2019. Assessment of sediment and organic carbon exports into the Arctic ocean: the case of the Yenisei River basin. Water Res. 158 (4), 118-135.

[26] Fedorova, I., Chetverova, A., Bolshiyanov, D., Makarov, A., Boike, J., Heim, B., Morgenstern, A., Overduin, P.P., Wegner, C., Kashina, V., Eulenburg, A., Dobrotina, E., Sidorina, I., 2015. Lena Delta hydrology and geochemistry: long-term hydrological data and recent field observations. Biogeosciences 12 (2), 345-363.

[27] Frolova, N.L., Belyakova, P.A., Grigoriev, V.Y., Sazonov, A.A., Zotov, L.V., Jarsjö J., 2017. Runoff fluctuations in the Selenga River Basin. Reg. Environ. Change 17 (7), 1965-1976.

[28] Fu, G., Charles, S.P., Chiew, F.H.S., 2007. A two-parameter climate elasticity of streamflow index to assess climate change effects on annual streamflow. Water Resour. Res. 43 (11), 1-12.

[29] Galy, V., Peucker-Ehrenbrink, B., Eglinton, T., 2015. Global carbon export from the terrestrial biosphere controlled by erosion. Nature 521 (7551), 204-207.

[30] Geyman, E.C., Douglas, M.M., Avouac, J.-P., Lamb, M.P., 2024. Permafrost slows Arctic riverbank erosion. Nature 634 (8033), 359-365.

[31] Gislason, S.R., Oelkers, E.H., Eiriksdottir, E.S., Kardjilov, M.I., Gisladottir, G., Sigfusson, B., Snorrason, A., Elefsen, S., Hardardottir, J., Torssander, P., Oskarsson, N., 2009. Direct evidence of the feedback between climate and weathering. Earth Planet. Sci. Lett. 277 (1), 213-222.

[32] Gordeev, V.V., Kravchishina, M.D., 2009. In:River Flux of Dissolved Organic Carbon (DOC) and Particulate Organic Carbon (POC) to the Arctic Ocean: What Are the Consequences of the Global Changes? Environmental Security. Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-9460-6_11.

[33] Griffin, C.G., McClelland, J.W., Frey, K.E., Fiske, G., Holmes, R.M., 2018. Quantifying CDOM and DOC in major Arctic rivers during ice-free conditions using Landsat TM and ETM+ data. Remote Sens. Environ. 209, 395-409.

[34] Grosse, G., Harden, J., Turetsky, M., McGuire, A.D., Camill, P., Tarnocai, C., Frolking, S., Schuur, E.A.G., Jorgenson, T., Marchenko, S., Romanovsky, V., Wickland, K.P., French, N., Waldrop, M., Bourgeau-Chavez, L., Striegl, R.G., 2011. Vulnerability of high-latitude soil organic carbon in North America to disturbance. J. Geophys. Res.: Biogeosci. 116 (G4), G00K06.

[35] Guo, L., Macdonald, R.W., 2006. Source and transport of terrigenous organic matter in the upper Yukon River: evidence from isotope ( d 13 C, D 14 C, and d 15 N) composition of dissolved, colloidal, and particulate phases. Global Biogeochem. Cycles 20 (2), GB2011.

[36] Guo, L., Ping, C.-L., Macdonald, R.W., 2007. Mobilization pathways of organic carbon from permafrost to arctic rivers in a changing climate. Geophys. Res. Lett. 34 (13), L13603.

[37] Han, J., Liu, Z., Woods, R., McVicar, T.R., Yang, D., Wang, T., Hou, Y., Guo, Y., Li, C., Yang, Y., 2024. Streamflow seasonality in a snow-dwindling world. Nature 629 (8014), 1075-1081.

[38] Harris, I., Osborn, T.J., Jones, P., Lister, D., 2020. Version 4 of the CRU TS monthly high-resolution gridded multivariate climate dataset. Sci. Data 7 (1), 109.

[39] Hengl, T., Wheeler, I., 2018. Soil organic carbon content in x 5 g / kg at 6 standard depths (0, 10, 30, 60, 100 and 200 cm) at 250 m resolution (v0.2). Zenodo. https://doi.org/10.5281/zenodo.2525553.

[40] Hilton, R.G., 2017. Climate regulates the erosional carbon export from the terrestrial biosphere. Geomorphology 277, 118-132.

[41] Hilton, R.G., Galy, V., Gaillardet, J., Dellinger, M., Bryant, C., O’Regan, M., Gröcke, D.R., Coxall, H., Bouchez, J., Calmels, D., 2015. Erosion of organic carbon in the Arctic as a geological carbon dioxide sink. Nature 524 (7563), 84-87.

[42] Holmes, R.M., Coe, M.T., Fiske, G.J., Gurtovaya, T., McClelland, J.W., Shiklomanov, A.I., Spencer, R.G.M., Tank, S.E., Zhulidov, A.V., 2012a. Climate change impacts on the hydrology and biogeochemistry of Arctic Rivers. In: Goldman C.R., Kumagai M., Robarts R.D. (Eds.), Climatic Change and Global Warming of Inland Waters: Impacts and Mitigation for Ecosystems and Societies, First Edition. John Wiley & Sons Ltd, pp. 1-26. doi:10.1002/9781118470596.ch1.

[43] Holmes, R.M., McClelland, J.W., Peterson, B.J., Tank, S.E., Bulygina, E., Eglinton, T.I., Gordeev, V.V., Gurtovaya, T.Y., Raymond, P.A., Repeta, D.J., Staples, R., Striegl, R. G., Zhulidov, A.V., Zimov, S.A., 2012b. Seasonal and annual fluxes of nutrients and organic matter from large rivers to the Arctic Ocean and surrounding seas. Estuaries Coasts 35 (2), 369-382.

[44] Horan, K., Hilton, R.G., Dellinger, M., Tipper, E., Galy, V., Calmels, D., Selby, D., Gaillardet, J., Ottley, C.J., Parsons, D.R., Burton, K.W., 2019. Carbon dioxide emissions by rock organic carbon oxidation and the net geochemical carbon budget of the Mackenzie River Basin. Am. J. Sci. 319 (6), 473-499.

[45] Jones, M.W., Coppola, A.I., Santín, C., Dittmar, T., Jaffé R., Doerr, S.H., Quine, T.A., 2020. Fires prime terrestrial organic carbon for riverine export to the global oceans. Nat. Commun. 11 (1), 2791.

[46] Jung, H., Ahn, J., Iwahana, G., Lee, J., 2025. Understanding water flowpaths and origins in an Arctic Alaskan basin: Implications for permafrost hydrology under global warming. Adv. Clim. Change Res. 16 (2), 361-372.

[47] Keskitalo, K.H., Bröder, L., Jong, D., Zimov, N., Davydova, A., Davydov, S., Tesi, T., Mann, P.J., Haghipour, N., Eglinton, T.I., Vonk, J.E., 2022. Seasonal variability in particulate organic carbon degradation in the Kolyma River, Siberia. Environ. Res. Lett. 17 (3), 034007.

[48] Krickov, I.V., Lim, A.G., Manasypov, R.M., Loiko, S.V., Shirokova, L.S., Kirpotin, S.N., Karlsson, J., Pokrovsky, O.S., 2018. Riverine particulate C and N generated at the permafrost thaw front: case study of western Siberian rivers across a 1700-km latitudinal transect. Biogeosciences 15 (22), 6867-6884.

[49] Krickov, I.V., Lim, A.G., Manasypov, R.M., Loiko, S.V., Vorobyev, S.N., Shevchenko, V. P., Dara, O.M., Gordeev, V.V., Pokrovsky, O.S., 2020. Major and trace elements in suspended matter of western Siberian rivers: first assessment across permafrost zones and landscape parameters of watersheds. Geochim. Cosmochim. Acta 269, 429-450.

[50] Krickov, I.V., Lim, A.G., Shirokova, L.S., Korets, M.A., Karlsson, J., Pokrovsky, O.S., 2023. Environmental controllers for carbon emission and concentration patterns in Siberian rivers during different seasons. Sci. Total Environ. 859, 160202.

[51] Krickov, I.V., Serikova, S., Pokrovsky, O.S., Vorobyev, S.N., Lim, A.G., Siewert, M.B., Karlsson, J., 2021. Sizable carbon emission from the floodplain of Ob River. Ecol. Indic. 131, 108164.

[52] Lal, R., 2003. Soil erosion and the global carbon budget. Environ. Int. 29 (4), 437-450.

[53] Langhorst, T., Pavelsky, T., 2023. Global observations of riverbank erosion and accretion from Landsat imagery. J. Geophys. Res.: Earth Surf. 128 (2), e2022JF 006774.

[54] Lesack, L.F.W., Marsh, P., Hicks, F.E., Forbes, D.L., 2013. Timing, duration, and magnitude of peak annual water-levels during ice breakup in the Mackenzie Delta and the role of river discharge. Water Resour. Res. 49 (12), 8234-8249.

[55] Li, M., Peng, C., He, N., 2022. Global patterns of particulate organic carbon export from land to the ocean. Ecohydrology 15 (2), 1-12.

[56] Li, M., Peng, C., Wang, M., Xue, W., Zhang, K., Wang, K., Shi, G., Zhu, Q., 2017. The carbon flux of global rivers: a re-evaluation of amount and spatial patterns. Ecol. Indic. 80 (1), 40-51.

[57] Lin, P., Pan, M., Wood, E.F., Yamazaki, D., Allen, G.H., 2021. A new vector-based global river network dataset accounting for variable drainage density. Sci. Data 8 (1), 28.

[58] Lininger, K.B., Wohl, E., 2019. Floodplain dynamics in north American permafrost regions under a warming climate and implications for organic carbon stocks: a review and synthesis. Earth Sci. Rev. 193, 24-44.

[59] Linke, S., Lehner, B., Ouellet Dallaire, C., Ariwi, J., Grill, G., Anand, M., Beames, P., Burchard-Levine, V., Maxwell, S., Moidu, H., Tan, F., Thieme, M., 2019. Global hydro-environmental sub-basin and river reach characteristics at high spatial resolution. Sci. Data 6 (1), 283.

[60] Liu, S., Wang, P., Huang, Q., Yu, J., Pozdniakov, S.P., Kazak, E.S., 2022a. Seasonal and spatial variations in riverine DOC exports in permafrost-dominated Arctic river basins. J. Hydrol. 612, 128060.

[61] Liu, S., Wang, P., Yu, J., Wang, T., Cai, H., Huang, Q., Pozdniakov, S.P., Zhang, Y., Kazak, E.S., 2022b. Mechanisms behind the uneven increases in early, mid- and late winter streamflow across four Arctic river basins. J. Hydrol. 606, 127425.

[62] Lobbes, J.M., Fitznar, H.P., Kattner, G., 2000. Biogeochemical characteristics of dissolved and particulate organic matter in Russian rivers entering the Arctic Ocean. Geochim. Cosmochim. Acta 64 (17), 2973-2983.

[63] Luo, X., Bai, X., Tan, Q., Ran, C., Chen, H., Xi, H., Chen, F., Wu, L., Li, C., Zhang, S., Zhong, X., Tian, S., 2022. Particulate organic carbon exports from the terrestrial biosphere controlled by erosion. CATENA 209, 105815.

[64] Makarieva, O., Nesterova, N., Post, D.A., Sherstyukov, A., Lebedeva, L., 2019. Warming temperatures are impacting the hydrometeorological regime of Russian rivers in the zone of continuous permafrost. Cryosphere 13 (6), 1635-1659.

[65] Mann, P.J., Strauss, J., Palmtag, J., Dowdy, K., Ogneva, O., Fuchs, M., Bedington, M., Torres, R., Polimene, L., Overduin, P., Mollenhauer, G., Grosse, G., Rachold, V., Sobczak, W.V., Spencer, R.G.M., Juhls, B., 2022. Degrading permafrost river catchments and their impact on Arctic Ocean nearshore processes. AMBIO 51 (2), 439-455.

[66] Marwick, T.R., Tamooh, F., Teodoru, C.R., Borges, A.V., Darchambeau, F., Bouillon, S., 2015. The age of river-transported carbon: a global perspective. Global Biogeochem. Cycles 29 (2), 122-137.

[67] Mayorga, E., Seitzinger, S.P., Harrison, J.A., Dumont, E., Beusen, A.H.W., Bouwman, A. F., Fekete, B.M., Kroeze, C., Van Drecht, G., 2010. Global Nutrient Export from WaterSheds 2 (NEWS 2): Model development and implementation. Environ. Modell. Softw. 25 (7), 837-853.

[68] McClelland, J.W., Holmes, R.M., Dunton, K.H., Macdonald, R.W., 2011. The Arctic Ocean estuary. Estuaries Coasts 35 (2), 353-368.

[69] McClelland, J.W., Holmes, R.M., Peterson, B.J., Raymond, P.A., Striegl, R.G., Zhulidov, A.V., Zimov, S.A., Zimov, N., Tank, S.E., Spencer, R.G.M., Staples, R., Gurtovaya, T. Y., Griffin, C.G., 2016. Particulate organic carbon and nitrogen export from major Arctic rivers. Global Biogeochem. Cycles 30 (5), 629-643.

[70] McClelland, J.W., Tank, S.E., Spencer, R.G.M., Shiklomanov, A.I., Zolkos, S., Holmes, R. M., 2023a. Arctic Great Rivers Observatory. Water Quality Dataset Version, 20230314

[71] McClelland, J.W., Tank, S.E., Spencer, R.G.M., Shiklomanov, A.I., Zolkos, S., Holmes, R. M., 2023. Arctic Great Rivers Observatory. Discharge Dataset, Version 20231204.

[72] Meybeck, M., Vörösmarty, C., 1999. Global transfer of carbon by rivers. Global Change Newsletter 37, 18-19.

[73] Nielsen, D.M., Chegini, F., Maerz, J., Brune, S., Mathis, M., Dobrynin, M., Baehr, J., Brovkin, V., Ilyina, T., 2024. Reduced Arctic Ocean CO₂ uptake due to coastal permafrost erosion. Nat. Clim. Change 14 (9), 968-975.

[74] Nihoul, J.C.J., Kostianoy, A.G., 2009. Influence of climate change on the changing Arctic and Sub-Arctic conditions. Springer Publishing Company Incorporated, Netherlands.

[75] Obu, J., Westermann, S., Barboux, C., Bartsch, A., Delaloye, R., Grosse, G., Heim, B., Hugelius, G., Irrgang, A., Kääb, A.M., Kroisleitner, C., Matthes, H., Nitze, I., Pellet, C., Seifert, F.M., Strozzi, T., Wegmüller, U., Wieczorek, M., Wiesmann, A., 2021. ESA Permafrost Climate Change Initiative (Permafrost_cci): Permafrost active layer thickness for the Northern Hemisphere, v3.0. NERC EDS Centre for Environmental Data Analysis, 28 June 2021.

[76] Obyazov, V.A., Smakhtin, V.K., 2013. Climate change effects on winter river runoff in Transbaikalia. Russ. Meteorol. Hydrol. 38 (7), 503-508.

[77] Ogneva, O., Mollenhauer, G., Juhls, B., Sanders, T., Palmtag, J., Fuchs, M., Grotheer, H., Mann, P.J., Strauss, J., 2023. Particulate organic matter in the Lena River and its delta: from the permafrost catchment to the Arctic Ocean. Biogeosciences 20 (7), 1423-1441.

[78] Ohmura, A., Wild, M., 2002. Is the hydrological cycle accelerating? Science 298 (5597), 1345-1346.

[79] Obu., Westermann, S., Kääb, A., Bartsch, A., 2019. Ground Temperature Map, 2000-2016, Northern Hemisphere Permafrost, PANGAEA.

[80] Olsen, A., Anderson, L.G., Heinze, C., 2015. Arctic carbon cycle: Patterns, impacts and possible changes. The New Arctic. B. Evengård, J. Nymand Larsen and Ø. Paasche. Cham, Springer International Publishing, pp. 95-115.

[81] Panagos, P., Borrelli, P., Meusburger, K., Yu, B., Klik, A., Jae Lim, K., Yang, J.E., Ni, J., Miao, C., Chattopadhyay, N., Sadeghi, S.H., Hazbavi, Z., Zabihi, M., Larionov, G.A., Krasnov, S.F., Gorobets, A.V., Levi, Y., Erpul, G., Birkel, C., Hoyos, N., Naipal, V., Oliveira, P.T.S., Bonilla, C.A., Meddi, M., Nel, W., Al Dashti, H., Boni, M., Diodato, N., Van Oost, K., Nearing, M., Ballabio, C., 2017. Global rainfall erosivity assessment based on high-temporal resolution rainfall records. Sci. Rep. 7 (1), 4175.

[82] Park, S.-W., Mun, J.-H., Lee, H., Steinert, N.J., An, S.-I., Shin, J., Kug, J.-S., 2025. Continued permafrost ecosystem carbon loss under net-zero and negative emissions. Sci. Adv. 11 (7), eadn8819.

[83] Peterson, B.J., Holmes, R.M., McClelland, J.W., Vorosmarty, C.J., Lammers, R.B., Shiklomanov, A.I., Shiklomanov, I.A., Rahmstorf, S., 2002. Increasing river discharge to the Arctic Ocean. Science 298 (5601), 2171-2173.

[84] Ping, C.-L., Michaelson, G.J., Jorgenson, M.T., Kimble, J.M., Epstein, H., Romanovsky, V.E., Walker, D.A., 2008. High stocks of soil organic carbon in the north American Arctic region. Nat. Geosci. 1 (9), 615-619.

[85] Pokrovsky, O., Lim, A., Kritskov, I., Korets, M., Shirokova, L., Vorobyev, S., 2022. Hydrochemistry of medium-size pristine rivers in Boreal and Subarctic Zone: Disentangling effect of landscape parameters across a permafrost, climate, and vegetation gradient. Water 14 (14), 2250.

[86] Rawlins, M.A., Steele, M., Holland, M.M., Adam, J.C., Cherry, J.E., Francis, J.A., Groisman, P.Y., Hinzman, L.D., Huntington, T.G., Kane, D.L., Kimball, J.S., Kwok, R., Lammers, R.B., Lee, C.M., Lettenmaier, D.P., McDonald, K.C., Podest, E., Pundsack, J.W., Rudels, B., Serreze, M.C., Shiklomanov, A., Skagseth, Ø., Troy, T.J., Vörösmarty, C.J., Wensnahan, M., Wood, E.F., Woodgate, R., Yang, D., Zhang, K., Zhang, T., 2010. Analysis of the Arctic system for freshwater cycle intensification: Observations and expectations. J. Clim. 23 (21), 5715-5737.

[87] Robertson, A.I., Bunn, S.E., Boon, P.I., Walker, K.F., 1999. Sources, sinks and transformations of organic carbon in Australian floodplain rivers. Mar. Freshwater Res. 50 (8), 813-829.

[88] Rowland, J.C., Schwenk, J.P., Shelef, E., Muss, J., Ahrens, D., Stauffer, S., Pilliouras, A., Crosby, B., Chadwick, A., Douglas, M.M., Kemeny, P.C., Lamb, M.P., Li, G.K., Vulis, L., 2023. Scale-dependent influence of permafrost on riverbank erosion rates. J. Geophys. Res.: Earth Surf. 128 (7), e2023JF 007101.

[89] Runkel, R.L., Crawford, C.G., Cohn, T.A., 2004. Load estimator (LOADEST): a FORTRAN program for estimating constituent loads in streams and rivers. Tech. Methods Rep., 4-A5 https://doi.org/10.3133/tm4A5.

[90] Seitzinger, S.P., Harrison, J.A., Dumont, E., Beusen, A.H.W., Bouwman, A.F., 2005. Sources and delivery of carbon, nitrogen, and phosphorus to the coastal zone: an overview of global nutrient export from watersheds (NEWS) models and their application. Global Biogeochem. Cycles 19 (4), GB4S01.

[91] Semiletov, I.P., Pipko, I.I., Shakhova, N.E., Dudarev, O.V., Pugach, S.P., Charkin, A.N., McRoy, C.P., Kosmach, D., Gustafsson, Ö., 2011. Carbon transport by the Lena River from its headwaters to the Arctic Ocean, with emphasis on fluvial input of terrestrial particulate organic carbon vs. carbon transport by coastal erosion. Biogeosciences 8 (9), 2407-2426.

[92] Smith, S.V., Renwick, W.H., Buddemeier, R.W., Crossland, C.J., 2001. Budgets of soil erosion and deposition for sediments and sedimentary organic carbon across the conterminous United States. Global Biogeochem. Cycles 15 (3), 697-707.

[93] St. Jacques, J. -M., Sauchyn, D.J., 2009. Increasing winter baseflow and mean annual streamflow from possible permafrost thawing in the Northwest Territories, Canada. Geophys. Res. Lett. 36 (1), L01401.

[94] Stallard, R.F., 1998. Terrestrial sedimentation and the carbon cycle: Coupling weathering and erosion to carbon burial. Global Biogeochem. Cycles 12 (2), 231-257.

[95] Strauss, J., Laboor, S., Schirrmeister, L., Fedorov, A.N., Fortier, D., Froese, D.G., Fuchs, M., Günther, F., Grigoriev, M.N., Harden, J.W., Hugelius, G., Jongejans, L.L., Kanevskiy, M.Z., Kholodov, A.L., Kunitsky, V., Kraev, G., Lozhkin, A.V., Rivkina, E., Shur, Y., Siegert, C., Spektor, V., Streletskaya, I., Ulrich, M., Vartanyan, S.L., Veremeeva, A., Walter Anthony, K.M., Wetterich, S., Zimov, N.S., Grosse, G., 2022. Database of Ice-Rich Yedoma Permafrost Version 2 (IRYP v2), PANGAEA. 10.1594/PANGAEA.940078.

[96] Streletskiy, D.A., Tananaev, N.I., Opel, T., Shiklomanov, N.I., Nyland, K.E., Streletskaya, I.D., Tokarev, I., Shiklomanov, A.I., 2015. Permafrost hydrology in changing climatic conditions: seasonal variability of stable isotope composition in rivers in discontinuous permafrost. Environ. Res. Lett. 10 (9), 095003.

[97] Striegl, R.G., Dornblaser, M.M., Aiken, G.R., Wickland, K.P., Raymond, P.A., 2007. Carbon export and cycling by the Yukon, Tanana, and Porcupine rivers, Alaska, 2001-2005. Water Resour. Res. 43 (2), 1-9.

[98] Sutfin, N.A., Wohl, E.E., Dwire, K.A., 2016. Banking carbon: a review of organic carbon storage and physical factors influencing retention in floodplains and riparian ecosystems. Earth Surf. Processes Landforms 41 (1), 38-60.

[99] Syvitski, J.P.M., Vörösmarty, C.J., Kettner, A.J., Green, P., 2005. Impact of humans on the flux of terrestrial sediment to the global coastal ocean. Science 308 (5720), 376-380.

[100] Tank, J.L., Rosi-Marshall, E.J., Griffiths, N.A., Entrekin, S.A., Stephen, M.L., 2010. A review of allochthonous organic matter dynamics and metabolism in streams. J. N. Am. Benthol. Soc. 29 (1), 118-146.

[101] Tank, S.E., Frey, K.E., Striegl, R.G., Raymond, P.A., Holmes, R.M., McClelland, J.W., Peterson, B.J., 2012. Landscape-level controls on dissolved carbon flux from diverse catchments of the circumboreal. Global Biogeochem. Cycles 26 (4), GB0E02.

[102] Tape, K.D., Verbyla, D., Welker, J.M., 2011. Twentieth century erosion in Arctic Alaska foothills: the influence of shrubs, runoff, and permafrost. J. Geophys. Res.: Biogeosci. 116, G04024.

[103] Tian, H., Yang, Q., Najjar, R.G., Ren, W., Friedrichs, M.A.M., Hopkinson, C.S., Pan, S., 2015. Anthropogenic and climatic influences on carbon fluxes from eastern North America to the Atlantic Ocean: a process-based modeling study. J. Geophys. Res.: Biogeosci. 120 (4), 757-772.

[104] Tockner, K., Pennetzdorfer, D., Reiner, N., Schiemer, F., Ward, J.V., 1999. Hydrological connectivity, and the exchange of organic matter and nutrients in a dynamic river-floodplain system (Danube, Austria). Freshwater Biol. 41 (3), 521-535.

[105] Vandermause, R., Harvey, M., Zevenbergen, L., Ettema, R., 2021. River-ice effects on bank erosion along the middle segment of the Susitna river, Alaska. Cold Reg. Sci. Technol. 185, 103239.

[106] Vihma, T., Screen, J., Tjernström, M., Newton, B., Zhang, X., Popova, V., Deser, C., Holland, M., Prowse, T., 2016. The atmospheric role in the Arctic water cycle: a review on processes, past and future changes, and their impacts. J. Geophys. Res. Biogeosci. 121 (3), 586-620.

[107] Vonk, J.E., Drenzek, N.J., Hughen, K.A., Stanley, R.H.R., McIntyre, C., Montluçon, D.B., Giosan, L., Southon, J.R., Santos, G.M., Druffel, E.R.M., Andersson, A.A., Sköld, M., Eglinton, T.I., 2019. Temporal deconvolution of vascular plant-derived fatty acids exported from terrestrial watersheds. Geochim. Cosmochim. Acta 244 (1), 502-521.

[108] Vonk, J.E., Fritz, M., Speetjens, N.J., Babin, M., Bartsch, A., Basso, L.S., Bröder, L., Göckede, M., Gustafsson, Ö., Hugelius, G., Irrgang, A.M., Juhls, B., Kuhn, M.A., Lantuit, H., Manizza, M., Martens, J., O’Regan, M., Suslova, A., Tank, S.E., Terhaar, J., Zolkos, S., 2025. The land-ocean Arctic carbon cycle. Nat. Rev. Earth & Environ. 6 (2), 86-105.

[109] Wang, C.L., Qiu, Y.F., Hao, Z., Wang, J.J., Zhang, C.C., Middelburg, J.J., Wang, Y.P., Zou, X.Q., 2024. Global patterns of organic carbon transfer and accumulation across the land-ocean continuum constrained by radiocarbon data. Nat. Geosci. 17 (8), 778-786.

[110] Wang, D., Li, Z., Li, Z., Ma, W., Nie, X., Yi, Y., 2020. Point bars retained particulate organic carbon within a meandering river corridor in Zoige Basin of the Tibetan Plateau. J. Hydrol. 588, 125112.

[111] Wang, P., Huang, Q., Liu, S., Yu, J., Zhang, Y., Wang, T., Bai, B., Pozdniakov, S.P., Frolova, N.L., Liu, C., 2023. Arctic runoff changes and their driving mechanisms under rapid warming: A review. Acta Geographica Sinica 78 (11), 2718-2734 (in Chinese with English abstract).

[112] Wang, P., Huang, Q., Pozdniakov, S.P., Liu, S., Ma, N., Wang, T., Zhang, Y., Yu, J., Xie, J., Fu, G., Frolova, N.L., Liu, C., 2021. Potential role of permafrost thaw on increasing Siberian river discharge. Environ. Res. Lett. 16 (3), 034046.

[113] Wen, H., Sullivan, P.L., Billings, S.A., Ajami, H., Cueva, A., Flores, A., Hirmas, D.R., Koop, A.N., Murenbeeld, K., Zhang, X., Li, L., 2022. From soils to streams: Connecting terrestrial carbon transformation, chemical weathering, and solute export across hydrological regimes. Water Resour. Res. 58 (7), e2022WR032314.

[114] Wild, B., Andersson, A., Broder, L., Vonk, J., Hugelius, G., McClelland, J.W., Song, W., Raymond, P.A., Gustafsson, O., 2019. Rivers across the Siberian Arctic unearth the patterns of carbon release from thawing permafrost. Proc. Nat. Acad. Sci. U. S.A. 116 (21), 10280-10285.

[115] Wu, J., Mollenhauer, G., Stein, R., Köhler, P., Hefter, J., Fahl, K., Grotheer, H., Wei, B., Nam, S.-I., 2022. Deglacial release of petrogenic and permafrost carbon from the Canadian Arctic impacting the carbon cycle. Nat. Commun. 13 (1), 7172.

[116] Xavier, T., Orgogozo, L., Prokushkin, A., Alonso-González, E., Gascoin, S., Pokrovsky, O., 2024. Future permafrost degradation under climate change in a headwater catchment of Central Siberia: quantitative assessment with a mechanistic modelling approach. Cryosphere 18 (12), 5865.

[117] Zhang, H., Lauerwald, R., Ciais, P., Van, O.K., Guenet, B., Regnier, P., 2022. Global changes alter the amount and composition of land carbon deliveries to European rivers and seas. Commun. Earth Environ. 3 (1), 1-11.

[118] Zhang, S., Gan, T.Y., Bush, A.B.G., Zhang, G., 2023. Evaluation of the impact of climate change on the streamflow of major pan-Arctic river basins through machine learning models. J. Hydrol. 619, 129295.

[119] Zhao, M., Jacobs, L., Bouillon, S., Govers, G., 2021. Rapid soil organic carbon decomposition in river systems: effects of the aquatic microbial community and hydrodynamical disturbance. Biogeosciences 18 (4), 1511-1523.

[120] Zhong, X., Zhang, T., Kang, S., Wang, J., 2021. Spatiotemporal variability of snow cover timing and duration over the Eurasian continent during 1966-2012. Sci. Total Environ. 750 (1), 141670.

[121] Zhu, X., Jia, G., Xu, X., 2024. Wildfire emissions offset more permafrost ecosystem carbon sink in the 21st century. Earth’s Future 12 (10), e2024EF 005098.

[122] Ziese, M., Rauthe-Schöch, A., Becker, A., Finger, P., Rustemeier, E., Hänsel, S., Schneider, U., 2022. GPCC full data daily version 2022 at 1.0 ° : Daily land-surface precipitation from rain-gauges built on GTS-based and historic data. doi: 10.5676/DWD_GPCC/FD_D_V2022_100.