Abstract：
Although the impacts of exotic wetland plant invasions on native biodiversity, landscape features, and carbon-nitrogen cycles are well appreciated, biogeochemical consequences posed by ecological competition, such as the heterogeneity of dissolved organic matter (DOM) from plant detritus and its impact on the formation of reactive oxygen species, are poorly understood. Thus, this study delves into O2•- photogeneration potential of DOM derived from three different parts (stem, leaf, and panicle) of invasive Spartina alterniflora (SA) and native Phragmites australis (PA). It is found that DOM from the leaves of SA and the panicles of PA has a superior ability to produce O2•-. With more stable aromatic structures and a higher proportion of sulfur-containing organic compounds, SA-derived DOM generally yields more O2•- than that derived from PA. UVA exposure enhances the leaching of diverse DOM molecules from plant detritus. Based on the reported monitoring data and our findings, the invasion of SA is estimated to approximately double the concentration of O2•- in the surrounding water bodies. This study can help to predict the underlying biogeochemical impacts from the perspective of aquatic photochemistry in future scenarios of plant invasion, seawater intrusion, wetland degradation, and elevated solar UV radiation.
摘要：
尽管外来湿地植物入侵对本地生物多样性的影响，景观特征，和碳氮循环很受欢迎，生态竞争带来的生物地球化学后果，如植物碎屑中溶解有机物（DOM）的异质性及其对活性氧形成的影响，知之甚少。因此，本研究深入研究了来自三个不同部分的DOM的O2•-光生势(茎，leaf,和圆锥花序）的侵袭性互花米草（SA）和天然芦苇（PA）。发现来自SA的叶子和PA的圆锥花序的DOM具有优异的产生O2•-的能力。具有更稳定的芳族结构和更高比例的含硫有机化合物，SA衍生的DOM通常比PA衍生的DOM产生更多的O2·-。UVA暴露会增强植物碎屑中多种DOM分子的浸出。根据报告的监测数据和我们的发现，SA的入侵估计大约是周围水体中O2浓度的两倍。这项研究可以帮助从水生光化学的角度预测潜在的生物地球化学影响，在未来植物入侵的情况下，海水入侵,湿地退化，和升高的太阳紫外线辐射。
