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

受盐度变化影响的一系列非生物过程涉及光介导的反应和有机化合物的不同降解途径，包括改变的光氧化，光降解和有机物（OM）的光解。众所周知，阳光会使水道中的溶解性有机物（DOM）降解，氧化或矿化，从而在水面附近并最终在混合层中造成DOM组成结构的巨大变化。源自各种植被类型的DOM对光解降解的敏感性水平不同，具体取决于初始化学成分以及发生何种基质降解（例如盐度）。日光和盐度对来自三种优势营养物种小叶紫薇的浸出DOM降解的影响，确定了沿佛罗里达东北部沿河连续体的Juncus romerianus和Taxodium distichum。在连续的流通式光解系统中，在20h的时间内对来自这三种来源的去离子或海水基质中的渗滤液进行了辐照。白骨germinans和灯心草roemerinaus DOM容易降解在照射期间在所有的波长的吸光度通过降低所指示的，而落羽杉发现DOM在淡水基质中所有波长上的吸收率都增加了，但在海水中却没有增加。PARAFAC分析表明，光化学成分的差异以及吸光度和荧光随时间变化的百分比变化表明，整个河口连续体对DOM池的单个贡献的重要性和可变性。这项工作表征了三个单独的DOM来源的光化学特性，展示了对此主题的进一步研究的必要性，并探讨了盐度对独特的植物来源DOM降解DOM的影响。