Physical Sciences and Mathematics Commons^™

The Relative Importance Of Exogenous And Substrate-Derived Nitrogen For Microbial Growth During Leaf Decomposition, B. M. Cheever, J. R. Webster, E. E. Bilger, S. A. Thomas

School of Natural Resources: Faculty Publications

Heterotrophic microbes colonizing detritus obtain nitrogen (N) for growth by assimilating N from their substrate or immobilizing exogenous inorganic N. Microbial use of these two pools has different implications for N cycling and organic matter decomposition in the face of the global increase in biologically available N. We used sugar maple leaves labeled with ¹⁵N to differentiate between microbial N that had been assimilated from the leaf substrate (enriched with ¹⁵N) or immobilized from the water (natural abundance ¹⁵N:¹⁴N) in five Appalachian streams ranging in ambient NO₃-N concentrations from about 5 to 900 …