水源水库藻类功能群落演替特征及水质评价

Succession Characteristics of Algae Functional Groups and Water Quality Assessment in a Drinking Water Reservoir

为了解水源水库的藻类功能群落时空演替特征及水质变化,以李家河水库为例, 2018年9月~2019年6月对藻类及水质因子开展连续监测,采用功能类群划分方法对水库藻类进行了识别与分类,探讨了藻类功能群落与水质间关系,并结合WQI指数法进行水质评价.结果表明,本研究共获得藻类56种,隶属于4门28属,可划分为15个功能群类,其中优势藻类功能群落分别为B、 D、 G、 J、 L0、Mp、 P、 W1和X1;李家河水库藻类结构呈现明显的季节性特征,混合期藻密度明显低于分层期,其中混合期的主要功能藻种为小球藻和小环藻,分层期的主要功能藻种为舟形藻和针杆藻.冗余分析(RDA)表明,水温、混合层深度和RWCS指数是驱动藻类演替的主要因子;WQI分析结果显示李家河水体水质为"良好",混合期水质略好于分层期.本研究指出扬水曝气系统可改变藻类功能群落的演替特征,有效改善水源水库水质,保障了饮水供水安全.

To understand the temporal and spatial succession characteristics of algae functional communities and water quality changes in a drinking water reservoir, the Lijiahe Reservoir was selected to monitor variations in water quality and algae from September 2018 to June 2019. The algae community was classified into functional groups following the method proposed by Reynolds and Padisák. The relationship between algal functional community and water quality was discussed, and the water quality was assessed using the water quality index(WQI) method. The results showed that 56 species of algae were obtained, belonging to 4 families and 28 genera, which were divided into 15 functional groups. The dominant algae functional communities were B, D, G, J, L0, Mp, P, W1, and X1. The algae structure of Lijiahe Reservoir showed obvious seasonal characteristics. The algal density in the mixed period was significantly lower than that in the stratification period. The main functional algae in the mixed period were Chlorella and Cyclotella, but Navicula and Synedra were the dominant functional algae in the stratification period. Redundancy analysis showed that the water temperature, mixing depth, and relative water column stability index were the main factors driving algae succession. WQI analysis indicated that the water quality of Lijiahe Reservoir was "good", and the water quality during the mixed period was slightly better than that in the stratification period. This study demonstrates that water-lifting aerators can change the succession characteristics of algae functional groups, and effectively contribute to improvement in water quality in a drinking water reservoir.