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Journal Articles FEMS Microbiology Ecology Year : 2013

Regulation of soil organic C mineralisation at the pore scale

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1
Leo S. Ruamps
  • Function : Author
Naoise Nunan
Valerie Pouteau
  • Function : Author
Julie Leloup
Xavier Raynaud
Virginie Roy

Abstract

Little is known about the factors that regulate C mineralisation at the soil pore scale or how these factors vary throughout the pore network. This study sought to understand how the decomposition of organic carbon varies within the soil pore network and to determine the relative importance of local environmental properties relative to biological properties as controlling factors. This was achieved by sterilising samples of soil and reinoculating them with axenic bacterial suspensions using the matric potential to target different locations in the pore network. Carbon mineralisation curves were described with two-compartment first-order models to distinguish CO2 derived from the labile organic carbon released during sterilisation from CO2 derived from organic C unaffected by sterilisation. The data indicated that the size of the labile pool of organic C, possibly of microbial origin, varied as a function of location in the pore network but that the organic carbon unaffected by sterilisation did not. The mineralisation rate of the labile C varied with the bacterial type inoculated, but the mineralisation rate of the organic C unaffected by sterilisation was insensitive to bacterial type. Taken together, the results suggest that microbial metabolism is a less significant regulator of soil organic carbon decomposition than are microbial habitat properties.

Dates and versions

hal-01567154 , version 1 (21-07-2017)

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Leo S. Ruamps, Naoise Nunan, Valerie Pouteau, Julie Leloup, Xavier Raynaud, et al.. Regulation of soil organic C mineralisation at the pore scale. FEMS Microbiology Ecology, 2013, 86 (1), pp.26--35. ⟨10.1111/1574-6941.12078⟩. ⟨hal-01567154⟩
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