Microbes are the principle drivers of elemental turnover, as the biologically catalyzed reaction rates often exceed the abiotic chemical transformations by orders of magnitudes. However, microbes are usually treated in a very rudimentary fashion in reactive transport models. Microbial metabolism With the onset of various omics and microbial ecology, a wealth of information becomes available that can be exploited and incorporated into biogeochemical models. We are incorporating in silico models of bacteria, as well as formulations that represent microbial traits into our reactive transport models. Micromodels Heterogeneity in both space and time is a characteristic of most natural environments. Reactive transport models commonly employ a continuum description. However, to account for variability in substrate concentrations at the pore scale, we have developed micromodels, explicitly resolving the local environment of microbes. Anaerobic methane oxidation in microbial aggregates The global biological CH4 cycle is largely controlled through microbial processes, and closely associated archaea and bacteria are thought to play a key role in the anaerobic oxidation of methane. In a collaboration with the Orphan Lab (Caltech), we are investigating the interactions between archaea and bacteria, combining nano-SIMS and FISH data with reactive transport modeling.
