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

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

*Corresponding author for this work

Research output: Contribution to journalArticle

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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 (10-105 km2) 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.

Original languageEnglish
Article number034028
JournalEnvironmental Research Letters
Volume13
Issue number3
Early online date28 Feb 2018
DOIs
Publication statusPublished - Mar 2018

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Keywords

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

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Environmental Science(all)
  • Public Health, Environmental and Occupational Health

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