泸沽湖水生生物群落及水生态环境质量研究

Study on Aquatic Community and Water Ecological Environment Quality of Lugu Lake

以云南泸沽湖水位站、水质站和水生态站2021年实测数据为研究材料,采用指标体系法(水位、水质、水生生物指标),对泸沽湖的水生态环境质量进行评估,探索建立适合于泸沽湖的水生态环境质量评价体系,以期为湖泊的水生态保护、修复与管理提供依据。结果显示:泸沽湖日平均水位均高于最低运行水位,最低运行水位均能得到保证;总体水质为Ⅰ类,水体清洁,属贫营养湖泊;浮游植物群落结构在种类组成上以绿藻门、硅藻门为主,转板藻、脆杆藻、星杆藻为优势种;浮游动物群落结构在种类组成上以轮虫、原生动物为主,侠盗虫、表壳虫、砂壳虫为优势种;砂壳虫、表壳虫、螺形龟甲轮虫、长刺异尾轮虫等是泸沽湖浮游动物的常见种,指示水体清洁;底栖动物群落结构在种类组成上以节肢动物门、软体动物门为主,优势种主要为齿斑摇蚊和多足摇蚊;浮游植物、浮游动物、底栖动物多样性一般,湖周断面多样性指数高于湖心断面,主汛期高于其他时段;水生态环境质量处于受干扰很小的最优状态。研究结果表明,转板藻以优势种出现在泸沽湖水体中对营养化进程是一种警示,应密切关注。

In order to provide a basis for the protection,restoration and management of lake Lugu,based on the measured data of reservoir stage gauging station,water quality stations and water ecological stations in Lugu Lake of Yunnan province in 2021,the evaluation index system method was used to explore a water ecological environment quality evaluation index system suitable for Lugu Lake,with the emphasis on water quantity,water quality and aquatic organisms.The results showed that the average daily water level of Lake Lugu was higher than the legal minimum operating water level,and the lowest ecological water level could meet the requirement.The water quality reaches class I standard and the water is clean.It’s an oligotrophic lake.The phytoplankton community composition is mainly composed of Chlorophyta and Bacillariophyta,and the dominant species are Mougeotia,Fragilaria and Asterionella.The zooplankton community is mainly composed of Rotifer and Protozoa,and is dominated by Strobilidium,Arcella and Difflugia.Difflugia,Arcella,Keratella cochlearis and Trichocerca longiseta are the common species of zooplankton which are indicator species of clean water.The plankton community structure is stable.The composition of the benthic community is Arthropoda—Mollusca,and the dominant species are Stictochironomus and Polypedilum.The diversity of phytoplankton,zooplankton and benthonic fauna are general.The diversity index of the monitoring sections around the lake are higher than that of the central section,and that of the main flood season was higher than other periods.The water ecological environment quality is in the optimal state with little disturbance.This study indicates that the occurrence of Mougeotia,which is a dominant species,is a warning to the eutrophication of water and should be pay more attention.