University of Oulu

Pedron, S., Xu, X., Walker, J., Ferguson, J., Jespersen, R., Welker, J., . . . Czimczik, C. (2021). TIME-INTEGRATED COLLECTION OF CO2 FOR 14C ANALYSIS FROM SOILS. Radiocarbon, 63(4), 1303-1319. doi:10.1017/RDC.2021.42

Time-integrated collection of CO₂ for ¹⁴C analysis from soils

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Author: Pedron, Shawn1; Xu, X.1; Walker, J. C.2;
Organizations: 1Department of Earth System Science, University of California, Irvine, CA, USA
2A. E. Lalonde AMS Laboratory, Ottawa, ON, Canada
3Environment and Natural Resources Institute, University of Alaska, Anchorage, USA
4Department of Biological Sciences University of Alaska, Anchorage, USA
5University of Oulu, Oulu, Finland
6UArctic, Rovaniemi, Lapland, Finland
7Department of Geological Sciences University of Alaska, Anchorage, USA
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1 MB)
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Language: English
Published: Cambridge University Press, 2021
Publish Date: 2021-10-26


We developed a passive sampler for time-integrated collection and radiocarbon (¹⁴C) analysis of soil respiration, a major flux in the global C cycle. It consists of a permanent access well that controls the CO₂ uptake rate and an exchangeable molecular sieve CO₂ trap. We tested how access well dimensions and environmental conditions affect collected CO₂, and optimized cleaning procedures to minimize ¹⁴CO₂ memory. We also deployed two generations of the sampler in Arctic tundra for up to two years, collecting CO₂ over periods of 3 days–2 months, while monitoring soil temperature, volumetric water content, and CO₂ concentration. The sampler collects CO₂ at a rate proportional to the length of a silicone tubing inlet (7–26 µg CO₂-C day⁻¹·m Si⁻¹). With constant sampler dimensions in the field, CO₂ recovery is best explained by soil temperature. We retrieved 0.1–5.3 mg C from the 1st and 0.6–13 mg C from the 2nd generation samplers, equivalent to uptake rates of 2–215 (n=17) and 10–247 µg CO₂-C day⁻¹ (n=20), respectively. The method blank is 8 ± 6 µg C (mean ± sd, n=8), with a radiocarbon content (fraction modern) ranging from 0.5875–0.6013 (n=2). The sampler enables more continuous investigations of soil C emission sources and is suitable for Arctic environments.

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Series: Radiocarbon
ISSN: 0033-8222
ISSN-E: 1945-5755
ISSN-L: 0033-8222
Volume: 63
Issue: 4
Pages: 1303 - 1319
DOI: 10.1017/RDC.2021.42
Type of Publication: A1 Journal article – refereed
Field of Science: 1172 Environmental sciences
Funding: Funding was provided by the U.S. NSF OPP (#1649664 to C.I.C., #1650084 to J.M.W. and E.S.K.).
Copyright information: © The Author(s), 2021. Published by Cambridge University Press for the Arizona Board of Regents on behalf of the University of Arizona. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (, which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.