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

[摘要] This paper deals with the simulation of microbial degradation of organicmatter in soil within the pore space at a microscopic scale. Pore space wasanalysed with micro-computed tomography and described using a sphere networkcoming from a geometrical modelling algorithm. The biological model wasimproved regarding previous work in order to include the transformation ofdissolved organic compounds and diffusion processes. We tested our modelusing experimental results of a simple substrate decomposition experiment(fructose) within a simple medium (sand) in the presence of differentbacterial strains. Separate incubations were carried out in microcosms usingfive different bacterial communities at two different water potentials of−10 and −100 cm of water. We calibrated the biological parameters bymeans of experimental data obtained at high water content, and we tested themodel without changing any parameters at low water content. Same as for theexperimental data, our simulation results showed that the decrease in watercontent caused a decrease of mineralization rate. The model was able tosimulate the decrease of connectivity between substrate and microorganism duethe decrease of water content.

[学科分类] 地球化学与岩石