Journal ArticleDOI
Separating root and soil microbial contributions to soil respiration: A review of methods and observations
TLDR
In this article, three primary methods have been used to distinguish hetero- versus autotrophic soil respiration including integration of components contributing to in situ forest soil CO2 efflux (i.e., litter, roots, soil), comparison of soils with and without root exclusion, and application of stable or radioactive isotope methods.Abstract:
Forest soil respiration is the sum of heterotrophic (microbes, soil fauna) and auto- trophic (root) respiration. The contribution of each group needs to be understood to evaluate implications of environmental change on soil carbon cycling and sequestration. Three primary methods have been used to distinguish hetero- versus autotrophic soil respiration including: integration of components contributing to in situ forest soil CO2 efflux (i.e., litter, roots, soil), comparison of soils with and without root exclusion, and application of stable or radioactive isotope methods. Each approach has advantages and disadvantages, but isotope based methods provide quantitative answers with the least amount of disturbance to the soil and roots. Pub- lished data from all methods indicate that root/rhizosphere respiration can account for as little as 10 percent to greater than 90 percent of total in situ soil respiration depending on vegetation type and season of the year. Studies which have integrated percent root contribution to total soil respiration throughout an entire year or growing season show mean values of 45.8 and 60.4 percent for forest and nonforest vegetation, respectively. Such average annual values must be extrapolated with caution, however, because the root contribution to total soil respiration is commonly higher during the growing season and lower during the dormant periods of the year. Abbreviations: TScer -t otal soil CO 2 efflux rate; f - fractional root contribution to TS cer; RC - root contribution to TScerread more
Citations
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Journal ArticleDOI
Adjustment of forest ecosystem root respiration as temperature warms.
TL;DR: Modelling efforts that allow root respiration to increase exponentially with temperature, with Q(10) values of 2 or more, may over-predict root contributions to ecosystem CO2 efflux for future climates and underestimate the amount of C available for other uses, including net primary productivity.
Journal ArticleDOI
Component greenhouse gas fluxes and radiative balance from two deltaic marshes in Louisiana: Pairing chamber techniques and eddy covariance
Ken W. Krauss,Guerry O. Holm,Brian C. Perez,David E. McWhorter,Nicole Cormier,Rebecca F. Moss,Darren J. Johnson,Scott C. Neubauer,Richard C. Raynie +8 more
TL;DR: In this article, the authors describe the net ecosystem exchange (NEEc) of CO2 and CH4 using eddy covariance (EC) in comparison with fluxes of CO 2, CH4, and N2O using chambers from brackish and freshwater marshes in Louisiana, USA.
Journal ArticleDOI
Interannual and seasonal changes in the soil exchange rates of monoterpenes and other VOCs in a Mediterranean shrubland
TL;DR: In this article, the authors explored and quantified soil VOC exchange rates in a Mediterranean shrubland and their seasonality using GC-MS and PTR-MS techniques, together with soil temperature, soil moisture and soil CO2 efflux measurements.
Journal ArticleDOI
Effects of Soil Cover and Land-Use on the Relations Flux-Concentration of Trace Gases
P.-A. Jacinthe,Rattan Lal +1 more
TL;DR: In this article, fluxes and soil air concentrations of CO2, CH4, and N2O were monitored for 17 months at three central Ohio sites, including a bare (vegetation-free) soil, a mulch (covered with
Journal ArticleDOI
Soil CO2 production in upland tundra where permafrost is thawing
TL;DR: In this paper, the authors used soil profile CO2 measurements to understand the response of belowground C emissions for different soil depths from upland tundra as a result of permafrost thaw and thermokarst development.
References
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Journal ArticleDOI
The global carbon dioxide flux in soil respiration and its relationship to vegetation and climate
TL;DR: In this article, measured rates of soil respiration from terrestrial and wetland ecosystems were used to define the annual global CO 2 flux from soils, to identify uncertainties in the global flux estimate, and to investigate the influences of temperature, precipitation, and vegetation.
Journal ArticleDOI
Carbon Isotopes in PhotosynthesisFractionation techniques may reveal new aspects of carbon dynamics in plants
TL;DR: The fractionation of carbon isotopes that occurs during photosynthesis is one of the most useful techniques for investigating the efficiency of CO2 uptake and indicates that different strategies are needed for improving wateruse efficiency in different kinds of plants.
Journal ArticleDOI
Soil respiration and the global carbon cycle
TL;DR: In this paper, the authors provide a brief review for policymakers who are concerned that changes in soil respiration may contribute to the rise in CO2 in Earth's atmosphere, while simultaneously leaving a greater store of carbon in the soil.
Journal ArticleDOI
Model estimates of CO2 emissions from soil in response to global warming
TL;DR: In this article, the Rothamsted model is used to calculate the amount of CO2 that would be released from the world stock of soil organic matter if temperatures increase as predicted, the annual return of plant debris to the soil being held constant.
Journal ArticleDOI
Plant decomposition and soil respiration in terrestrial ecosystems
J. S. Singh,S. R. Gupta +1 more
TL;DR: In this article, a review deals with methodological approaches, measured rates, and environmental control of two major interdependent processes regulating the structure and function of terrestrial ecosystems, viz., plant decomposition and soil respiration.