Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 11, issue 8
Biogeosciences, 11, 2201–2209, 2014
https://doi.org/10.5194/bg-11-2201-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 11, 2201–2209, 2014
https://doi.org/10.5194/bg-11-2201-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 22 Apr 2014

Research article | 22 Apr 2014

Simulating microbial degradation of organic matter in a simple porous system using the 3-D diffusion-based model MOSAIC

O. Monga1, P. Garnier2, V. Pot2, E. Coucheney3, N. Nunan3, W. Otten4, and C. Chenu5 O. Monga et al.
  • 1UMMISCO-Cameroun, Unité Mixte Internationale de recherche UMMISCO, Université de Yaoundé 1 (Cameroun), Institut de Recherche pour le Développement (IRD), Université de Paris 6, Paris, France
  • 2INRA, AgroParisTech, UMR1091 EGC, 78850, Thiverval-Grignon, France
  • 3CNRS, UMR7618 – Biogéochimie et Ecologie des Milieux Continentaux, 78850, Thiverval-Grignon, France
  • 4The SIMBIOS Centre, University of Abertay Dundee, Kydd Building, Dundee, DD1 1HG, UK
  • 5AgroParisTech, UMR7618 – Biogéochimie et Ecologie des Milieux Continentaux, 8850, Thiverval-Grignon, France

Abstract. This paper deals with the simulation of microbial degradation of organic matter in soil within the pore space at a microscopic scale. Pore space was analysed with micro-computed tomography and described using a sphere network coming from a geometrical modelling algorithm. The biological model was improved regarding previous work in order to include the transformation of dissolved organic compounds and diffusion processes. We tested our model using experimental results of a simple substrate decomposition experiment (fructose) within a simple medium (sand) in the presence of different bacterial strains. Separate incubations were carried out in microcosms using five different bacterial communities at two different water potentials of −10 and −100 cm of water. We calibrated the biological parameters by means of experimental data obtained at high water content, and we tested the model without changing any parameters at low water content. Same as for the experimental data, our simulation results showed that the decrease in water content caused a decrease of mineralization rate. The model was able to simulate the decrease of connectivity between substrate and microorganism due the decrease of water content.

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