Modelling microbially mediated redox processes in lake sediments

Sena, C.*; Molinero, J.*; Nagaoka, Toru*; Ajima, Shuji*; Ito, Tsuyoshi; Sasaki, Yoshito ; Asano, Takahiro; Yoshikawa, Hideki

The oxidation of organic matter and reduction of inorganic components may play an important role in the geochemical evolution of deep geological repository. A jar-fermentor experiment with water and sediment samples was made, in order to assess the role of microbial respiration in the geochemical evolution of aquatic systems. During the experiment, the main geochemical parameters have been measured both in the aqueous phase and the headspace gas. A numerical model has been developed in order to quantify the role of each bacterial group that is believed to influence the geochemical evolution of both the aqueous and gaseous phases of the jar-fermentor. Numerical results show good agreement with measured data. Model results show that the initial concentration of bacteria, which is usually an unknown of the experiments, plays an important role in numerical results.