Contrasting responses of DOM leachates to photodegradation observed in plant species collected along an estuarine salinity gradient

Abstract A series of abiotic processes affected by salinity changes involve light-mediated reactions and different degradation pathways organic compounds, including altered photo-oxidation, photo-degradation, photolysis matter (OM). Sunlight is known to degrade, oxidize, or mineralize dissolved (DOM) in waterways, creating large compositional structure DOM near the water surface ultimately mixed layer. derived from various vegetation types has differing levels susceptibility photolytic depending on initial chemical composition what matrix takes place (e.g., salinity). The effect sunlight leached three dominant vegetative species, Avicennia germinans , Juncus romerianus Taxodium distichum along a riverine continuum northeast Florida was determined. Leachates these sources deionized seawater were irradiated continuous flow-through system over course 20 h. roemerinaus readily degraded as indicated decreases absorbance across all wavelengths during irradiation period, while found increase freshwater matrix, but not seawater. PARAFAC analysis differences photochemical components % change fluorescence time indicate importance variability individual contributions pool an estuarine continuum. This work characterizes properties sources, exhibits need for further research this topic, explores photo-degradation unique plant-derived DOM.