Cellular and non-cellular mineralization of organic carbon in soils with contrasted physicochemical properties

It has been recently demonstrated that soil organic carbon (SOC) mineralization is supported by intracellular respiration of heterotrophic microorganisms and by non-cellular oxidative processes. However, little is known about the prevalence and drivers of non-cellular SOC mineralization among soils....

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Published in:Soil biology & biochemistry 2018-10, Vol.125, p.286-289
Main Authors: Kéraval, Benoit, Fontaine, Sébastien, Lallement, Audrey, Revaillot, Sandrine, Billard, Hermine, Alvarez, Gaël, Maestre, Fernando, Amblard, Christian, Lehours, Anne-Catherine
Format: Article
Language:English
Subjects:
Biodiversity and Ecology
carbon dioxide
catalysts
Dissolved organic carbon
Environmental Sciences
greenhouse gas emissions
Heterotrophic respiration
heterotrophs
mineralization
Mineralization processes
Non-cellular mineralization
oxygen
oxygen consumption
redox reactions
soil enzymes
soil organic carbon
soil properties
soil respiration
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Summary:It has been recently demonstrated that soil organic carbon (SOC) mineralization is supported by intracellular respiration of heterotrophic microorganisms and by non-cellular oxidative processes. However, little is known about the prevalence and drivers of non-cellular SOC mineralization among soils. In this study, untreated and gamma-irradiated soils sampled along a latitudinal gradient and exhibiting contrasted physicochemical properties were incubated in order to quantify potential non-cellular SOC mineralization and to identify its sensibility to soil properties. In sterilized and unsterilized soils, CO2 emission mirrored O2 consumption signifying the presence of several coupled redox reactions transferring electrons from organic C to intermediate acceptors and to O2. This supports the idea that non-cellular mineralization results from extracellular oxidative metabolisms catalyzed by soil enzymes and/or abiotic catalysts. Our findings also show that non-cellular SOC mineralization is ubiquitous and contributes to 24% of soil respiration on average. Cellular and non-cellular SOC mineralization are positively linked but the contribution of non-cellular processes to soil CO2 emissions increases with dissolved organic carbon concentration. •Non-cellular soil organic C mineralization (RNON-CELLULAR) is widespread in contrasted soils.•Non-cellular processes may sustains 24% of global SOC mineralization.•RNON-CELLULAR shows a greater sensitivity to DOC content compared to RCELLULAR.
ISSN:0038-0717
1879-3428
DOI:10.1016/j.soilbio.2018.07.023