Amino acid, peptide and protein mineralization dynamics in a taiga forest soil

► High molecular weight dissolved organic nitrogen dominates the soluble N pool in taiga forests. ► Spatial stratification in soil N cycling and availability were apparent within the soil profile. ► Rates of organic N breakdown followed the series Protein < Peptide = Amino Acids. ► Rates of organic N breakdown were faster than rates of nitrification. ► Calculated rates of C and N flux through the microbial biomass were very similar.