A field-based method for simultaneous measurements of the ¹⁸O and ¹³C soil CO₂ efflux

B. Mortazavi (1) , J. L. Prater (1) , J. P. Chanton (1)

1 FSU - Florida State University [Tallahassee]

Three approaches for determining the stable isotopic composition (¹³C and ¹⁸O) of soil CO₂ efflux were compared. A new technique employed mini-towers, constructed of open topped piping, that were placed on the soil surface to collect soil-emitted CO₂. Samples were collected along a vertical gradient and analyzed for CO₂ concentration and isotopic composition. These data were then used to produce a Keeling plot to determine the ¹⁸O and ¹³C of CO₂ emitted from the soil. These results were then compared to the ¹⁸O and ¹³C of soil respired CO₂ measured with two other techniques: (1) flux chambers and (2) estimation from the application of the diffusional fractionation factor to measured values of belowground soil ¹⁸O CO₂ and to CO₂ in equilibrium with soil water ¹⁸O. Mini-tower ¹⁸O Keeling plots were linear and highly significant (0.81

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Astrophysique [astro-ph]; Interfaces continentales, environnement; Océan, Atmosphère; Sciences de la Terre

B. Mortazavi, J. L. Prater, J. P. Chanton. A field-based method for simultaneous measurements of the ¹⁸O and ¹³C soil CO₂ efflux. Biogeosciences Discussions, 2004, 1 (1), pp.1-25. ⟨hal-00297724⟩