Differential mobilization of terrestrial carbon pools in Eurasian Arctic river basins
Year: 2013
Type: article
Abstract: Mobilization of Arctic permafrost carbon is expected to increase with warming-induced thawing. However, this effect is challenging to assess due to the diverse processes controlling the release of various organic carbon (OC) pools from heterogeneous Arctic landscapes. Here, by radiocarbon dating various terrestrial OC components in fluvially and coastally integrated estuarine sediments, we present a unique framework for deconvoluting the contrasting mobilization mechanisms of surface vs. deep (permafrost) carbon pools across the climosequence of the Eurasian Arctic. Vascular plant-derived lignin phenol (14)C contents reveal significant inputs of young carbon from surface sources whose delivery is dominantly controlled by river runoff. In contrast, plant wax lipids predominantly trace ancient (permafrost) OC that is preferentially mobilized from discontinuous permafrost regions, where hydrological conduits penetrate deeper into soils and thermokarst erosion occurs more frequently. Because river runoff has significantly increased across the Eurasian Arctic in recent decades, we estimate from an isotopic mixing model that, in tandem with an increased transfer of young surface carbon, the proportion of mobilized terrestrial OC accounted for by ancient carbon has increased by 3-6% between 1985 and 2004. These findings suggest that although partly masked by surface carbon export, climate change-induced mobilization of old permafrost carbon is well underway in the Arctic.
Institutions: ETH Zurich, Geological Institute, Woods Hole Oceanographic Institution, Utrecht University, University of Manchester, Stockholm University, Bolin Centre for Climate Research, Russian Academy of Sciences, University of Alaska Fairbanks, V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Sciences, International Arctic Research Center, University of Copenhagen
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: green
Funders: National Science Foundation, Woods Hole Oceanographic Institution, Polarforskningssekretariatet, Eidgenössische Technische Hochschule Zürich, Knut och Alice Wallenbergs Stiftelse, Nordisk Ministerråd, Vetenskapsrådet, National Oceanic and Atmospheric Administration, Natural Environment Research Council, Russian Academy of Sciences
Awards: Effects of a warming climate on the key organic carbon cycle processes in the Eurasian Arctic, G2463850315, Influence of Pre- and Post-depositional Processes on Sedimentary Organic Matter Composition, G4705543499, Temporal Constraints on the Delivery of Terrestrial Organic Carbon to Marine Sediments, G7488253137, G8005595348, G8029585767, Constraints on Organic Carbon Inputs to Continental Margin Sediments: A Coupled Molecular Isotopic Approach
OpenAlex ID: W2155877774