Soil System Sciences

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

Monga, O., Garnier, P., Pot, V., Coucheney, E., Nunan, N., Otten, W., and Chenu, C.: Simulating microbial degradation of organic matter in a simple porous system using the 3-D diffusion-based model MOSAIC, Biogeosciences, 11, 2201-2209, doi:10.5194/bg-11-2201-2014, 2014.



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.


Biogeosciences (BG) is an international scientific journal dedicated to the publication and discussion of research articles, short communications and review papers on all aspects of the interactions between the biological, chemical and physical processes in terrestrial or extraterrestrial life with the geosphere, hydrosphere and atmosphere. The objective of the journal is to cut across the boundaries of established sciences and achieve an interdisciplinary view of these interactions. Experimental, conceptual and modelling approaches are welcome. More at Biogeosciences homepage.

Antonio Jordán is a Senior Lecturer at the University of Seville and coordinator of the MED Soil Research Group. Antonio’s research focusses on rainfall-induced soil erosion processes, the effects of wildfires on soil properties and soil degradation in Mediterranean areas. He is an active members of the Soil System Sciences (SSS) Division of the European Geosciences Union (EGU), which coordinates the scientific programme on soil sciences.