Siberian Arctic inland waters emit mostly contemporary carbon

peer reviewed Inland waters (rivers, lakes and ponds) are important conduits for the emission of terrestrial carbon in Arctic permafrost landscapes. These emissions are driven by turnover of contemporary terrestrial carbon and additional “pre-aged” (Holocene and late-Pleistocene) carbon released fro...

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Bibliographic Details
Main Authors: Dean, J, Meisel, O, Roscoe, MM, Marchesini, Garnett, M, Lenderink, H, van Logtestijn, R, Borges, Alberto, Bouillon, S, Lambert, T, Röckmann, T, Maximov, T, Petrov, R, Karsanaev, S, Aerts, R, van Huissteden, J, Vonk, J, Dolman, H
Other Authors: FOCUS - Freshwater and OCeanic science Unit of reSearch - ULiège
Format: Conference Object
Language:English
Published: 2020
Subjects:
Methane
CH4
méthane
lake
river
Life sciences
Aquatic sciences & oceanology
Sciences du vivant
Sciences aquatiques & océanologie
permafrost
Tundra
Siberia
Online Access:https://orbi.uliege.be/handle/2268/246466
https://orbi.uliege.be/bitstream/2268/246466/1/EGU2020-17416-print.pdf
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Summary:peer reviewed Inland waters (rivers, lakes and ponds) are important conduits for the emission of terrestrial carbon in Arctic permafrost landscapes. These emissions are driven by turnover of contemporary terrestrial carbon and additional “pre-aged” (Holocene and late-Pleistocene) carbon released from thawing permafrost soils, but the magnitude of these source contributions to total inland water carbon fluxes remains unknown. Here we present unique simultaneous radiocarbon age measurements of inland water CO2, CH4 and dissolved and particulate organic carbon in northeast Siberia during summer. We show that >80% of total inland water carbon emissions were contemporary in age, but that pre-aged carbon contributed >50% at sites strongly affected by permafrost thaw. CO2 and CH4 were younger than dissolved and particulate organic carbon, suggesting emissions were primarily fuelled by contemporary carbon decomposition. The study region was a net carbon sink (-876.9 ± 136.4 Mg C for 25 July to 17 August), but inland waters were a source of contemporary (16.8 Mg C) and pre-aged (3.7 Mg C) emissions that respectively offset 1.9 ± 1.2% and 0.4 ± 0.3% of CO2 uptake by tundra (‑897 ± 115 Mg C). Our findings reveal that inland water carbon emissions from permafrost landscapes may be more sensitive to changes in contemporary carbon turnover than the release of pre-aged carbon from thawing permafrost.

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