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Drought alters respired δ13CO2 from autotrophic, but not heterotrophic soil respiration


Risk, D and Nickerson, N and Phillips, CL and Kellman, L and Moroni, M, Drought alters respired δ13CO2 from autotrophic, but not heterotrophic soil respiration, Soil Biology and Biochemistry, 50, (7) pp. 26-32. ISSN 0038-0717 (2012) [Refereed Article]

Copyright Statement

2012 Published by Elsevier Ltd.

DOI: doi:10.1016/j.soilbio.2012.01.025


Many researchers are interested in the variability of root-respired δ13CO2 as an indication of linkages between belowground plant respiration and canopy processes. Most studies in this area have, however, relied upon the assumption that temporal variability of total soil respired δ13CO2 reflects autotrophic soil processes, but in fact few supporting measurements of purely autotrophic soil respiration (partitioned from total soil respiration) are available. Here we use a combination of physical and isotopic partitioning methodologies to track the variability in autotrophic and heterotrophic soil δ13CO2 at five sites in Eastern Canada during a very dry growing season. Three dimensional modeling of soil isotopic transport dynamics in the static sampling chambers allow us to constrain measurement bias and to eliminate non-steady-state effects as a potential driver of observed variability. We provide experimental results that support a pivotal assumption made in prior interpretations of soil δ13CO2 dynamics: we observed minimal isotopic variability in soil microbial δ13CO2 efflux, but appreciable temporal variability in root-respired δ13CO2 at sites where near drought conditions were observed, suggesting that isotopic discrimination is likely linked to seasonal variations in transpirational demand.

Item Details

Item Type:Refereed Article
Keywords:soil respiration, carbon, isotropes, partitioning, autotrophic, heterotropic
Research Division:Environmental Sciences
Research Group:Soil sciences
Research Field:Soil biology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the environmental sciences
UTAS Author:Moroni, M (Dr Martin Moroni)
ID Code:116483
Year Published:2012
Web of Science® Times Cited:28
Deposited By:Plant Science
Deposited On:2017-05-10
Last Modified:2017-08-22

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