title: Biotic and abiotic factors affecting the delta(13)C of soil respired CO(2) in a Mediterranean oak woodland.
abstract: The flux (R(s)) and carbon isotopic composition (delta(13)C (Rs)) of soil respired CO (2) was measured every 2 h over the course of three diel cycles in a Mediterranean oak woodland, together with measurements of the delta(13)C composition of leaf, root and soil organic matter (delta(13)C (SOM)) and metabolites. Simulations of R(s) and delta(13)C (Rs) were also made using a numerical model parameterised with the SOM data and assuming short-term production rates were driven mainly by temperature. Average values of delta(13)C (Rs) over the study period were within the range of root metabolite and average delta(13)C (SOM) values, but enriched in (13)C relative to the bulk delta(13)C of leaf, litter, and roots and the upper soil organic layers. There was good agreement between model output and observed CO (2) fluxes and the underlying features of delta(13)C (Rs). Observed diel variations of 0.5 per thousand in delta(13)C (Rs) were predicted by the model in response to temperature-related shifts in production rates along a approximately 3 per thousand gradient observed in the profile of delta(13)C (SOM). However, observed delta(13)C (Rs) varied by over 2 per thousand, indicating that both dynamics in soil respiratory metabolism and physical processes can influence short-term variability of delta(13)C (Rs).
authors.affiliation: BIOEMCO (UMR 7618), Universite de Pierre et Marie Curie, Paris, France.
authors.forename: Kadmiel
authors.initials: K
authors.lastname: Maseyk
authors.forename: Lisa
authors.initials: L
authors.lastname: Wingate
authors.forename: Ulli
authors.initials: U
authors.lastname: Seibt
authors.forename: Jaleh
authors.initials: J
authors.lastname: Ghashghaie
authors.forename: Camille
authors.initials: C
authors.lastname: Bathellier
authors.forename: Pedro
authors.initials: P
authors.lastname: Almeida
authors.forename: Raquel
authors.initials: R
authors.lastname: Lobo de Vale
authors.forename: Joao S
authors.initials: JS
authors.lastname: Pereira
authors.forename: Dan
authors.initials: D
authors.lastname: Yakir
authors.forename: Maurizio
authors.initials: M
authors.lastname: Mencuccini
mesh_terms: D001673:Biodegradation, Environmental; D002245:Carbon Dioxide / Q000737:chemistry* / Q000378:metabolism; D002247:Carbon Isotopes / Q000737:chemistry*; D017753:Ecosystem; D019083:Mediterranean Region; D010788:Photosynthesis; D018515:Plant Leaves; D029963:Quercus; D012987:Soil; D012988:Soil Microbiology; D013696:Temperature
chemical_list: D002247:Carbon Isotopes; D012987:Soil; D002245:Carbon Dioxide