Decomposition of Dissolved Organic Carbon and Nitrogen Compounds From Leaves in an Experimental Hard‐water Stream1

Addition of dry hickory and maple leaves, enclosed in nylon mesh, for 30 hr to a recirculating stream increased dissolved organic carbon (DOC) levels nearly 10‐fold. Bacterial populations which developed rapidly decomposed labile organic carbon and nitrogen compounds in the leaf leachate within 72 hr. Bacteriologically labile and refractory dissolved organic carbon fractions, with T½ decomposition rates of 2 and 80 days, respectively, were present in the leachate. Most refractory dissolved organic nitrogen compounds persisted unmodified for at least 24 days. The processing capacity of woodland streams for natural dissolved organic compounds is much greater than previously believed.