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Research article2018Peer reviewedOpen access

Permafrost and lakes control river isotope composition across a boreal Arctic transect in the Western Siberian lowlands

Ala-aho, P.; Soulsby, C.; Pokrovsky, O. S.; Kirpotin, S. N.; Karlsson, J.; Serikova, S.; Manasypov, R.; Lim, A.; Krickov, I.; Kolesnichenko, L. G.; Laudon, H.; Tetzlaff, D.

Abstract

The Western Siberian Lowlands (WSL) store large quantities of organic carbon that will be exposed and mobilized by the thawing of permafrost. The fate of mobilized carbon, however, is not well understood, partly because of inadequate knowledge of hydrological controls in the region which has a vast low-relief surface area, extensive lake and wetland coverage and gradually increasing permafrost influence. We used stable water isotopes to improve our understanding of dominant landscape controls on the hydrology of the WSL. We sampled rivers along a 1700 km South-North transect from permafrost-free to continuous permafrost repeatedly over three years, and derived isotope proxies for catchment hydrological responsiveness and connectivity. We found correlations between the isotope proxies and catchment characteristics, suggesting that lakes and wetlands are intimately connected to rivers, and that permafrost increases the responsiveness of the catchment to rainfall and snowmelt events, reducing catchment mean transit times. Our work provides rare isotope-based field evidence that permafrost and lakes/wetlands influence hydrological pathways across a wide range of spatial scales (10-10(5) km(2)) and permafrost coverage (0%-70%). This has important implications, because both permafrost extent and lake/wetland coverage are affected by permafrost thaw in the changing climate. Changes in these hydrological landscape controls are likely to alter carbon export and emission via inland waters, which may be of global significance.

Keywords

stable water isotopes; Western Siberia Lowlands; mean transit time; hydrological connectivity; permafrost

Published in

Environmental Research Letters
2018, Volume: 13, number: 3, article number: 034028
Publisher: IOP PUBLISHING LTD

    Sustainable Development Goals

    SDG6 Clean water and sanitation

    UKÄ Subject classification

    Oceanography, Hydrology, Water Resources

    Publication identifier

    DOI: https://doi.org/10.1088/1748-9326/aaa4fe

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/94535