Seasonal effects on the stoichiometry of microbes, primary production, and nutrient cycling

We develop a compartment model inspired by producer–herbivore–microbe soil food webs and determine how the naturally occurring seasonal variation in producer and detrital quality affects microbial nutrient cycling and the feedback to primary production. We show that seasonal changes in the stoichiometric quality of the producer coupled with the efficiency of herbivore grazing could induce a switch in the stoichiometric signature and therefore the functioning of the microbial community. Microbial decomposers are responsible for the flux of essential nutrients through an ecosystem. Our model enables one to quantitatively understand the tipping points between bacterially or fungally dominated decomposer communities, and more generally, the complex relationships between microbial decomposers, primary production, and nutrient cycling.