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Isotope partitioning of soil respiration: A Bayesian solution to accommodate multiple sources of variability

Journal Article · · Journal of Geophysical Research. Biogeosciences
DOI:https://doi.org/10.1002/2014JG002794· OSTI ID:1454917
 [1];  [2]
  1. Arizona State Univ., Tempe, AZ (United States). School of Life Sciences; Arizona State University
  2. Univ. of Western Sydney, NSW (Australia). Hawkesbury Inst. for the Environment; Univ. of Wyoming, Laramie, WY (United States). Dept. of Botany. Program in Ecology
Isotopic methods offer great potential for partitioning trace gas fluxes such as soil respiration into their different source contributions. Traditional partitioning methods face challenges due to variability introduced by different measurement methods, fractionation effects, and end-member uncertainty. To address these challenges, we describe in this paper a hierarchical Bayesian (HB) approach for isotopic partitioning of soil respiration that directly accommodates such variability. We apply our HB method to data from an experiment conducted in a shortgrass steppe ecosystem, where decomposition was previously shown to be stimulated by elevated CO2. Our approach simultaneously fits Keeling plot (KP) models to observations of soil or soil-respired δ13C and [CO2] obtained via chambers and gas wells, corrects the KP intercepts for apparent fractionation (Δ) due to isotope-specific diffusion rates and/or method artifacts, estimates method- and treatment-specific values for Δ, propagates end-member uncertainty, and calculates proportional contributions from two distinct respiration sources (“old” and “new” carbon). The chamber KP intercepts were estimated with greater confidence than the well intercepts and compared to the theoretical value of 4.4‰, our results suggest that Δ varies between 2 and 5.2‰ depending on method (chambers versus wells) and CO2 treatment. Because elevated CO2 plots were fumigated with 13C-depleted CO2, the source contributions were tightly constrained, and new C accounted for 64% (range = 55–73%) of soil respiration. The contributions were less constrained for the ambient CO2 treatments, but new C accounted for significantly less (47%, range = 15–82%) of soil respiration. Finally, our new HB partitioning approach contrasts our original analysis (higher contribution of old C under elevated CO2) because it uses additional data sources, accounts for end-member bias, and estimates apparent fractionation effects.
Research Organization:
Arizona State Univ., Tempe, AZ (United States); Univ. of Wyoming, Laramie, WY (United States)
Sponsoring Organization:
National Science Foundation (NSF) (United States); USDA Cooperative State Research, Education, and Extension Service (CSREES); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Grant/Contract Number:
SC0006973
OSTI ID:
1454917
Alternate ID(s):
OSTI ID: 1402370
Journal Information:
Journal of Geophysical Research. Biogeosciences, Journal Name: Journal of Geophysical Research. Biogeosciences Journal Issue: 2 Vol. 120; ISSN 2169-8953
Publisher:
American Geophysical UnionCopyright Statement
Country of Publication:
United States
Language:
English

References (58)

A numerical evaluation of chamber methodologies used in measuring the δ 13 C of soil respiration journal September 2009
Challenges in measuring the δ13C of the soil surface CO2 efflux journal December 2010
The BUGS project: Evolution, critique and future directions journal July 2009
Bayesian Data—Model Integration in Plant Physiological and Ecosystem Ecology book January 2008
Wetting and drying cycles drive variations in the stable carbon isotope ratio of respired carbon dioxide in semi-arid grassland journal March 2009
Bias and uncertainty of δ13CO2 isotopic mixing models journal December 2009
Uncertainty in source partitioning using stable isotopes journal July 2001
Biological and physical influences on the carbon isotope content of CO2 in a subalpine forest snowpack, Niwot Ridge, Colorado journal September 2008
Combining MCMC with ‘sequential’ PKPD modelling journal January 2009
Partitioning the components of soil respiration: a research challenge journal June 2006
The stable isotopic composition of modern soil carbonate and its relationship to climate journal December 1984
The concentration and isotopic abundances of atmospheric carbon dioxide in rural areas journal January 1958
On the isotopic composition of carbon in soil carbon dioxide journal November 1991
Stable Isotope Constraints on Net Ecosystem Production Under Elevated CO2 book January 2005
The isotopic composition of soil and soil-respired CO2 journal February 1998
A model for soil CO2 production and transport 1: journal July 1999
Sensitivity analysis and quantification of uncertainty for isotopic mixing relationships in carbon cycle research journal January 2006
Evaluation of carbon isotope fractionation of soil CO2 under an advective–diffusive regimen: A tool for computing the isotopic composition of unfractionated deep source journal June 2007
Sources of CO2 efflux from soil and review of partitioning methods journal March 2006
Soil organic matter dynamics in grassland soils under elevated CO2: Insights from long-term incubations and stable isotopes journal October 2007
Characterizing the impact of diffusive and advective soil gas transport on the measurement and interpretation of the isotopic signal of soil respiration journal March 2010
13C fractionation at the root–microorganisms–soil interface: A review and outlook for partitioning studies journal September 2010
Drought alters respired δ13CO2 from autotrophic, but not heterotrophic soil respiration journal July 2012
Towards a more plant physiological perspective on soil ecology journal October 2006
Separating root and soil microbial contributions to soil respiration: A review of methods and observations journal January 2000
Elevated atmospheric CO 2 effects and soil water feedbacks on soil respiration components in a Colorado grassland : ELEVATED ATMOSPHERIC CO journal May 2003
The application and interpretation of Keeling plots in terrestrial carbon cycle research journal March 2003
Partitioning net ecosystem exchange of CO 2 : A comparison of a Bayesian/isotope approach to environmental regression methods : PARTITIONING NET ECOSYSTEM EXCHANGE journal September 2007
Keeling plots are non‐linear in non‐steady state diffusive environments journal January 2009
Physical controls on the isotopic composition of soil-respired CO 2 journal January 2009
Persistent wind-induced enhancement of diffusive CO 2 transport in a mountain forest snowpack journal January 2011
Carbon isotope discrimination during photosynthesis and the isotope ratio of respired CO 2 in boreal forest ecosystems journal December 1996
Erratum: Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model journal December 2000
The fate of carbon in grasslands under carbon dioxide enrichment journal August 1997
Terrestrial ecosystem carbon dynamics and climate feedbacks journal January 2008
Temperature-associated increases in the global soil respiration record journal March 2010
Elevated CO 2 enhances water relations and productivity and affects gas exchange in C 3 and C 4 grasses of the Colorado shortgrass steppe. journal April 2001
Elevated CO2 stimulates soil respiration in a FACE wheat field journal January 2001
A global relationship between the heterotrophic and autotrophic components of soil respiration? journal October 2004
Diffusive fractionation complicates isotopic partitioning of autotrophic and heterotrophic sources of soil respiration: δ13C of soil respiration journal June 2010
Why environmental scientists are becoming Bayesians: Modelling with Bayes journal December 2004
Incorporating uncertainty and prior information into stable isotope mixing models journal May 2008
Rhizodeposition stimulated by elevated CO2 in a semiarid grassland journal May 2004
Carbon isotopes in terrestrial ecosystem pools and CO 2 fluxes journal April 2008
Metabolic origin of the δ 13 C of respired CO 2 in roots of Phaseolus vulgaris journal November 2008
Hierarchical statistical modeling of xylem vulnerability to cavitation journal February 2009
Systematic variations in the carbon and oxygen isotopic composition of pedogenic carbonate along elevation transects in the southern Great Basin, United States journal April 1989
Modularization in Bayesian analysis, with emphasis on analysis of computer models journal March 2009
Feedback and Modularization in a Bayesian Meta–analysis of Tree Traits Affecting Forest Dynamics journal March 2013
Source Partitioning Using Stable Isotopes: Coping with Too Much Variation journal March 2010
Merging Resource Availability with Isotope Mixing Models: The Role of Neutral Interaction Assumptions journal July 2011
Uncertainty and Variability in Demography and Population Growth: a Hierarchical Approach journal June 2003
Reconstructing Plant root area and Water Uptake Profiles journal July 2004
Hierarchical Bayesian statistics: merging experimental and modeling approaches in ecology journal April 2009
Beyond simple linear mixing models: process-based isotope partitioning of ecological processes journal January 2014
Bayesian Analysis of Errors-in-Variables Regression Models journal September 1995
Effect of water addition and nitrogen fertilization on the fluxes of CH4, CO2, NOx, and N2O following five years of elevated CO2 in the Colorado Shortgrass Steppe journal January 2003
Measuring and modelling the isotopic composition of soil respiration: insights from a grassland tracer experiment journal January 2011

Cited By (3)

Monitoring CO2 emissions to gain a dynamic view of carbon allocation to arbuscular mycorrhizal fungi journal August 2016
The value of soil respiration measurements for interpreting and modeling terrestrial carbon cycling journal November 2016
Modeling soil CO 2 production and transport with dynamic source and diffusion terms: testing the steady-state assumption using DETECT v1.0 journal January 2018

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