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Research article - Peer-reviewed, 2018

Increasing dominance of terrigenous organic matter in circumpolar freshwaters due to permafrost thaw

Wauthy, Maxime; Rautio, Milla; Christoffersen, Kirsten S; Forsström, Laura; Laurion, Isabelle; Mariash, Heather L.; Peura, Sari; Vincent, Warwick F.

Abstract

Climate change and permafrost thaw are unlocking the vast storage of organic carbon held in northern frozen soils. Here, we evaluated the effects of thawing ice‐rich permafrost on dissolved organic matter (DOM) in freshwaters by optical analysis of 253 ponds across the circumpolar North. For a subset of waters in subarctic Quebec, we also quantified the contribution of terrestrial sources to the DOM pool by stable isotopes. The optical measurements showed a higher proportion of terrestrial carbon and a lower algal contribution to DOM in waters affected by thawing permafrost. DOM composition was largely dominated (mean of 93%) by terrestrial substances at sites influenced by thawing permafrost, while the terrestrial influence was much less in waterbodies located on bedrock (36%) or with tundra soils unaffected by thermokarst processes (42%) in the catchment. Our results demonstrate a strong terrestrial imprint on freshwater ecosystems in degrading ice‐rich permafrost catchments, and the likely shift toward increasing dominance of land‐derived organic carbon in waters with ongoing permafrost thaw.

Keywords

freshwater; permafrost thaw; organic carbon; dissolved organic matter (DOM); greenhouse gases

Published in

Limnology and Oceanography Letters
2018, volume: 3, number: 3, pages: 186-198

Authors' information

Wauthy, Maxime
Université du Québec à Chicoutimi
Rautio, Milla
Université du Québec à Chicoutimi
Christoffersen, Kirsten S
University of Copenhagen
Forsström, Laura
University of Helsinki
Laurion, Isabelle
Laval University
Mariash, Heather L.
Environment Canada
Peura, Sari
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology
Vincent, Warwick F.
Laval University

UKÄ Subject classification

Oceanography, Hydrology, Water Resources

Publication Identifiers

DOI: https://doi.org/10.1002/lol2.10063

URI (permanent link to this page)

https://res.slu.se/id/publ/99524