Sporadic P limitation constrains microbial growth and facilitates SOM accumulation in the stoichiometrically coupled, acclimating microbe–plant–soil model

Requirements for biomass carbon (C), nitrogen (N), and phosphorus (P) constrain organism growth are important agents structuring ecosystems. Arctic tundra habitats strongly nutrient limited as decomposition recycling of nutrients slowed by low temperature. Modeling interactions among these elemental cycles affords an opportunity to explore how disturbances such climate change might differentially affect cycles. Here we introduce a C–N–P-coupled version the Stoichiometrically Coupled Acclimating Microbe-Plant-Soil (SCAMPS) model, “SCAMPS-CNP”, corresponding modified CN-only “SCAMPS-CN”. We compared SCAMPS-CNP SCAMPS-CN models project moderate (RCP 6.0) air warming scenario will impact tussock availability ecosystem C stocks. was characterized larger SOM smaller stocks SCAMPS-CN, greater reduction in under warming. This difference can largely be attributed microbial CNP which, instead being driven direct costs P acquisition, variable resource limitation due asynchronous C, N, demand. Warming facilitated relative increase plant SCAMPS-CNP, however, increased extracellular enzyme pools activity, which more than offset metabolic associated with their production. Although community able flexibly adapt its stoichiometry become bacteria-like (N-rich) both models, deviated further from target value model because need balance cellular NP ratio. Our results indicate that seasonality asynchrony resources predicted changes storage therefore build on growing body literature indicating should considered cycling projections.