B05

Project B05 focuses on interactions and niche differentiation of key microbial players involved in the formation and removal of nitrate across soils, aeration zone, and groundwater. Factors driving the locally high abundance of these key players and their interactions will be explored using a combination of incubation experiments, molecular and microscopy approaches, and 15N-based activity assays. Our key questions will address the role of complete ammonia oxidizers (comammox bacteria) in groundwater nitrification, and whether interactions between anammox bacteria and yet uncultured Nitrospirota performing dissimilatory nitrate reduction to ammonium support nitrogen loss.