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

Benoit Kéraval*, Sébastien Fontaine, Audrey Lallement, Sandrine Revaillot, Hermine Billard, Gaël Alvarez, Fernando Maestre, Christian Amblard, Anne Catherine Lehours

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)286-289
Number of pages4
JournalSoil Biology and Biochemistry
Volume125
DOIs
StatePublished - Oct 2018

Keywords

  • Dissolved organic carbon
  • Heterotrophic respiration
  • Mineralization processes
  • Non-cellular mineralization

ASJC Scopus subject areas

  • Microbiology
  • Soil Science

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