15N enrichment as an integrator of the effects of C and N on microbial metabolism and ecosystem function.

Organic carbon (C) and nitrogen (N) are essential for heterotrophic soil microorganisms, and their bioavailability strongly influences ecosystem C and N cycling. We show here that the natural (15)N abundance of the soil microbial biomass is affected by both the availability of C and N and ecosystem N processing. Microbial (15)N enrichment correlated negatively with the C : N ratio of the soil soluble fraction and positively with net N mineralization for ecosystems spanning semiarid, temperate and tropical climates, grassland and forests, and over four million years of ecosystem development. In addition, during soil incubation, large increases in microbial (15)N enrichment corresponded to high net N mineralization...

Categories: Publication; Types: Citation, Journal Citation; Tags: ?15?, Ecology Letters, N cycling, N mineralization, carbon and nitrogen availability, All tags... ecosystem function, resource availability, soil microbial biomass, stable isotopes, Fewer tags