A passive sampling method for radiocarbon analysis of soil respiration using molecular sieve

• Published in: Soil Biology and Biochemistry
• Main Authors: Garnett, Mark H, Hartley, Iain, Sommerkorn, Martin, Wookey, Philip
• Other Authors: NERC Radiocarbon Facility (Environment), Biological and Environmental Sciences, Macaulay Land Use Research Institute, orcid:0000-0001-5957-6424
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier (Pergamon) 2009
• Subjects: Soil respiration; CO2; Radiocarbon; Molecular sieve; Atmospheric carbon dioxide Environmental aspects; Global environmental change; Climatic changes Arctic regions; Climatic changes Environmental aspects; Arctic
• Online Access: http://hdl.handle.net/1893/1674; https://doi.org/10.1016/j.soilbio.2009.03.024; http://www.sciencedirect.com/science/journal/00380717; http://dspace.stir.ac.uk/bitstream/1893/1674/1/Revised%20submitted%2030JAN09_SBB35711.pdf

Radiocarbon analysis of soil CO2 can provide information on the age, source and turnover rate of soil organic C. We developed a new method for passively trapping respired CO2 on molecular sieve, allowing it to be returned to the laboratory and recovered for C isotope analysis. We tested the method on a soil at a grassland site, and using a synthetic soil created to provide a contrasting isotopic signature. As with other passive sampling techniques, a small amount of fractionation of the 13C isotope occurs during sampling, which we have quantified, otherwise the results show that the molecular sieve traps a sufficiently large and representative sample of CO2 for C isotope analysis. Since 14C results are routinely corrected for mass-dependent fractionation, our results show that passive sampling of soil respiration using molecular sieve offers a reliable method to collect soil-respired CO2 for 14C analysis.