程海湖夏冬季浮游植物群落结构与富营养化状况研究

为了解程海湖浮游植物群落特征及其富营养化现状,对程海湖的水体理化指标和浮游植物群落结构进行了系统调查,分析了夏、冬季节程海湖水质状况、浮游植物群落结构特征及其与环境因子之间的关系,并运用综合营养状态指数法和藻类生物学法评价了程海湖的营养状态.结果表明,调研期间程海湖氮、磷浓度较高,水体中总磷(TP)浓度为0.03～0.19 mg·L~(-1),总氮(TN)为0.38～3.08 mg·L~(-1),综合营养状态指数(TLI)在49.3～54.4之间波动,已经达到轻度富营养水平;藻密度变化范围为1.54×10~6～1.65×10~7个·L~(-1),已超过常规湖泊的水华暴发阈值范围;浮游植物以蓝藻、绿藻为主,Shannon-Wiener多样性指数大多数为1～3,Pielou均匀度指数为0.18～0.72,部分时间段藻类多样性偏低,呈现出典型的蓝藻门为优势的富营养化状态,亟需对其进行生态保护与管理.

Eutrophication status and phytoplankton community structure in Chenghai Lake in summer and winter

To evaluate phytoplankton community structure and trophic status in Chenghai Lake, the physicochemical indexes and phytoplankton community structure were systematically investigated. The characteristic of water quality and the relationship between phytoplankton community structure and environmental factors in the lake during summer and winter seasons were analyzed. The comprehensive trophic status index method and algal biology method were used to evaluate the trophic status of Chenghai Lake. The results showed that the concentration of nitrogen and phosphorus was higher than before. Nutrient concentrations ranged from 0.03 to 0.19 mg·L^-1 for total phosphorus (TP) and from 0.38 to 3.08 mg·L^-1 for total nitrogen (TN), and the values of TLI was 49.3~54.4, which had reached the level of mild eutrophication. While the algal density ranged from 1.54×10⁶ to 1.65×10⁷ cells·L^-1, which had exceeded the threshold of algal bloom approved by other eutrophic lakes. Cyanobacteria and Chlorophyta were the dominant phyla of phytoplankton community. The Shannon-Wiener diversity index varied from 1 to 3, while the Pielou evenness index ranged from 0.18 to 0.72. The diversity of algae was low at some time during the survey, showing a typical eutrophication state with cyanobacteria as dominant species. Therefore, it is urgent to carry out ecological protection and management.