Oyster River leaf decomposition and leaching

Decomposition of leaf litter in streams provides an essential resource subsidy to aquatic ecosystems. Following seasonal litter pulses, dissolved organic matter (DOM) leaches from leaves almost immediately. This early mass loss is recognized as a physical process based on the solubility of certain foliar compounds. An underrecognized pathway of mass loss is through the generation of new soluble leaf material via microbial processing during the following weeks and months of decomposition. We used an in-situ leaf decomposition experiment paired with in-lab leaching protocols to quantify the amount of leachable DOM and nitrogen generated from leaves beyond the initial 24-72 hours of decomposition. We measured mass loss and additional leaching – termed late-stage leaching (LSL) – after 7, 14, and 28 days of decomposition from fast-decomposing (maple) and slow-decomposing (oak) leaves.