Time-integrated collection of CO₂ for ¹⁴C analysis from soils
Pedron, Shawn; Xu, X.; Walker, J. C.; Ferguson, J. C.; Jespersen, R. G.; Welker, J. M.; Klein, E. S.; Czimczik, C. I. (2021-06-18)
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
© 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 (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
https://creativecommons.org/licenses/by/4.0/
https://urn.fi/URN:NBN:fi-fe2021102652269
Tiivistelmä
Abstract
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.
Kokoelmat
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