Relationships between C and N availability, substrate age, and natural abundance 13C and 15N signatures of soil microbial biomass in a semiarid climate

Soil microbial organisms are central to carbon (C) and nitrogen (N) transformations in soils, yet not much is known about the stable isotope composition of these essential regulators of element cycles. We investigated the relationship between C and N availability and stable C and N isotope composition of soil microbial biomass across a three million year old semiarid substrate age gradient in northern Arizona. The δ15N of soil microbial biomass was on average 7.2‰ higher than that of soil total N for all substrate ages and 1.6‰ higher than that of extractable N, but not significantly different for the youngest and oldest sites. Microbial 15N enrichment relative to soil extractable and total N was low at the...

Categories: Publication; Types: Citation, Journal Citation; Tags: Microbial biomass, Natural isotopic abundance, Nitrogen and carbon availability, Nitrogen mineralization, Piñon–juniper, All tags... Semiarid, Soil Biology and Biochemistry, Stable isotopes, Substrate age gradient, Fewer tags