Modeling Microbial Adaptations to Nutrient Limitation During Litter Decomposition

Microbial decomposers face large stoichiometric imbalances when feeding on nutrient-poor plant residues. To meet the challenges of nutrient limitation, microorganisms might: (i) allocate less carbon (C) to growth vs. respiration or excretion (i.e., flexible C-use efficiency, CUE), (ii) produce extracellular enzymes target compounds that supply most limiting element, (iii) modify their cellular composition according external availability, and (iv) preferentially retain nutrients at senescence. These four resource use modes can have different consequences litter C nitrogen (N) dynamics–modes selectively remove from system reduce storage in soil, whereas delay mineralization increase internal N recycling could promote N. Since we do not know which are dominant decomposers, cannot predict fate released residues, particular under conditions microbial limitation. address this question, developed a process-based model decomposition these were implemented. We then parameterized using ?80 datasets spanning broad range qualities. The calibrated variants able capture variability C, N, lignin fractions during regardless included. This suggests lead similar trajectories (thanks multiple alternative acquisition pathways), identification is possible “standard” data (an equifinality problem). Our results thus point need exploring adaptations limitation with empirical estimates traits develop models enough consider hypothesized responses.