Although phages are abundant in soil, to date they have been neglected in soil biogeochemistry. In this Emmy Noether research group we will for the first time study how abiotic soil microhabitats govern phage infection and thus bacterial death and quantify the effects on plant nutrient and CO2 release as well as the stabilization of microbial residues. We will go beyond phenomenological descriptions to reveal the mechanisms of these processes, including direct dispersal limitations (e.g. phage sorption to mineral surfaces) and indirect effects (shaping traits of the phage community, with potential feedback to dispersal). The project will couple isotopic tracing techniques with phage isolation and culture-independent molecular methods to comprehensively characterize the interactions between the soil habitat, its bacterial inhabitants, and their viruses.