Microbial enzymatic responses to drought and to nitrogen addition in a southern California grassland

摘要: Microbial enzymes play a fundamental role in ecosystem processes and nutrient mineralization. Therefore understanding enzyme responses to anthropogenic environmental change is important for predicting function the future. In previous study, we used reciprocal transplant design examine direct indirect effects of drought nitrogen (N) fertilization on litter decomposition southern California grassland. This work showed negative decomposition, faster by N-adapted microbial communities N-fertilized plots than non-fertilized plots. Here measured biomass activities nine extracellular enzymatic mechanisms underlying N. We hypothesized that changes fungal potential activity (EEA) would relate directly responses. also predicted dominate community our semi-arid study site. However, found was dominated bacterial biomass, bacteria responded negatively treatment. contrast patterns most EEA increased response Potential decoupled from N These results suggest alter efficiencies EEA, defined as mass target substrate lost per unit EEA. Enzyme declined with treatment, possibly because reduced water availability immobilization diffusion rates. experiment, β-glucosidase, β-xylosidase, polyphenol oxidase were greater when microbes transplanted into environments which they originated. increase efficiency suggests may adapt their local environment. Overall, indicate addition have predictable impacts enzymes, providing means linking potentials in-situ activities.