Sampling soil-derived CO2 for analysis of isotopic composition: a comparison of different techniques

Citation

Bertolini T, Inglima I, Rubino M, Marzaioli F, Lubritto C, Subke J, Peressotti A & Cotrufo MF (2006) Sampling soil-derived CO2 for analysis of isotopic composition: a comparison of different techniques. Isotopes in Environmental and Health Studies, 42 (1), pp. 57-65. https://doi.org/10.1080/10256010500503312

Abstract
Anewsystem for soil respiration measurement [P. Rochette, L.B. Flanagan, E.G. Gregorich. Separating soil respiration into plant and soil components using analyses of the natural abundance of carbon-13. Soil Sci. Soc. Am. J., 63, 1207–1213 (1999).] was modified in order to collect soil-derived CO2 for stable isotope analysis. The aim of this study was to assess the suitability of this modified soil respiration system to determine the isotopic composition (δ13C) of soil CO2 efflux and to measure, at the same time, the soil CO2 efflux rate, with the further advantage of collecting only one air sample.A comparison between different methods of air collection from the soil was carried out in a laboratory experiment. Our system, as well as the other dynamic chamber approach tested, appeared to sample the soil CO2, which is enriched with respect to the soil CO2 efflux, probably because of a mass dependent fractionation during diffusion and because of the atmospheric contribution in the upper soil layer. On the contrary, the static accumulation of CO2 into the chamber headspace allows sampling of δ13C-CO2 of soil CO2 efflux.

Keywords
Carbon-13; Carbon dioxide; Measurement; Respiration; Sampling; Soil; Soil respiration; Climatic changes; Soil management Environmental aspects; Soil chemistry

Journal
Isotopes in Environmental and Health Studies: Volume 42, Issue 1