岩溶区水库冬季溶解有机质组成特征及来源:以桂林五里峡水库为例

Distinguishing the Properties and Sources of the Dissolved Organic Matter in Karst Reservoir Water During Winter Using Three-Dimensional Fluorescence Spectrum Technology: A Case Study in Wulixia Reservoir of Guangxi Province

近年来,三维荧光技术被广泛应用于研究天然水体中溶解有机质(DOM)的物理化学特性.为了解岩溶区水库水体溶解有机质的特征,利用三维荧光光谱并结合平行因子分析法研究桂林五里峡水库冬季水体中DOM分布特征及其来源,探讨其水化学特征以及初步估算DOM荧光组分的相对比例.结果表明,五里峡水库水体中的Ca^(2+)、HCO_3^-为主要阳阴离子,水体水化学主要受碳酸盐风化作用影响,DOC质量浓度占TOC质量浓度的91%;五里峡水库水体DOM在冬季主要由类富里酸、类腐殖酸和类色氨酸组成;荧光指数、腐殖化指标、自生源指标和新鲜度指数显示五里峡水库水体DOM在冬季整体呈现弱腐殖质化特征,自生源特征明显,微型光合生物对水体中DOM的形成起到至关重要的作用,说明水生微型生物的光合作用在岩溶碳循环中扮演着重要的角色.

In recent years,the fluorescence spectrum technology has been widely applied to study the physical and chemical properties of dissolved organic matter（ DOM） in natural water. In order to reveal the properties of the dissolved organic matter in reservoir water,the three-dimensional fluorescence spectrum and the parallel factor analysis were used to determine the properties of DOM and its sources in the Wulixia reservoir during the winter of 2016. Moreover,the chemical characteristics of water and the relative proportion of DOM fluorescent components were estimated. Results show that：（1） Ca2 ＋and HCO3^-are the main cations and anions in the Wulixia reservoir during winter. The water is mainly controlled by the carbonate balance system and dissolved organic carbon（ DOC） accounted for about 91% of total organic carbon（ TOC）.（2） DOM from the Wulixia reservoir can be divided into three components： fulvic acid,humic acid,and tryptophan.（3） The parameters,fluorescence index,humification index,biological index,and freshness index show the existence of DOM in the Wulixia reservoir. Microorganisms have a significant effect on DOM composition.