Changes in perturbation-correlation moving-window two-dimensional correlation spectroscopy of dissolved organic matter induced by dam regulation in a river-type reservoir

Background: Water levels in reservoirs are regulated by dams and thus affects the fate of dissolved organic matter(DOM). For more effective water management and natural watershed conservation, the correlation between dam regulation and DOM changes urgently needs to be explained. According to the regulation rules of Shuikou Reservoir dam, the monitoring times were determined to be September 2021, November 2021, January 2022 and May 2022, and the sampling sites covered Shili'an, Yangkeng, Liujia Bridge, Youxi reservoir entrance (downstream), Gutian Huangtian, Gutian Huangtian (downstream), Bay mouth, Xiongjiang River in Minqing, and Front of Shuikou Reservoir dam. Basic water quality parameters, such as temperature, pH, dissolved oxygen (DO), dissolved total nitrogen (DTN), total phosphorus (TP), dissolved organic carbon (DOC), NH4+, NO3-, turbidity, conductivity (us), as well as the components and concentrations of DOM, were collected at the time and space defined above.Methods: In this study, in-situ monitoring, field sampling, perturbation-correlation moving-window two-dimensional (PCMW2D) correlation spectroscopy technology and statistical methods were used orderly.Technique: Perturbation-correlation moving-window two-dimensional (PCMW2D) correlation spectroscopy technology was employed to analyze the DOM fluorescence components. Mantel tests were used to statistically evaluate the relationships between DOM fluorescence components and water quality parameters, as well as indicators of organic pollutants.

研究背景：水库水位由大坝调控，这会直接影响溶解有机质（dissolved organic matter，DOM）的赋存与归趋。为实现更高效的水资源管理与自然流域保护，亟需阐明大坝调控与DOM变化之间的关联机制。根据水口大坝的调控规则，本研究确定的监测时段为2021年9月、2021年11月、2022年1月及2022年5月；采样点位涵盖十里庵、洋坑、刘家桥、尤溪水库入口（下游段）、古田黄田、古田黄田（下游段）、湾口、闽清雄江以及水口大坝坝前。本研究在上述时空范围内采集了多项基础水质参数，包括温度、pH、溶解氧（dissolved oxygen，DO）、溶解态总氮（dissolved total nitrogen，DTN）、总磷（total phosphorus，TP）、溶解有机碳（dissolved organic carbon，DOC）、铵根离子（NH4+）、硝酸根离子（NO3-）、浊度、电导率（conductivity，us），以及DOM的组成与浓度。
研究方法：本研究依次采用原位监测、野外采样、扰动相关移动窗二维（perturbation-correlation moving-window two-dimensional，PCMW2D）相关光谱技术以及统计学分析方法。
分析技术：采用扰动相关移动窗二维相关光谱技术对DOM的荧光组分进行解析；通过曼特尔检验（Mantel test）统计学分析DOM荧光组分与水质参数及有机污染物指标之间的关联关系。