南四湖浮游植物群落结构特征及季相变化

Community Structure Characteristics and the Seasonal Variation of Phytoplankton in Lake Nansi

在南四湖内布点15个,于2010年3月、6月、9月、11月对浮游植物的群落特征进行调查分析。共获得浮游植物8门117种属,密度介于33×104个/L和2434×104个/L,平均为548×104个/L;生物量0.46 mg/L^25.9 mg/L,平均为6.45 mg/L;Shannon-Wiener多样性指数0.84~2.68之间,平均为1.76,季节变化为3月>6月>11月>9月;南四湖浮游植物的优势种群共有6种,蓝藻、硅藻各2种,绿藻、隐藻各1种。春季优势种群以小球藻和色球藻为主,秋冬季节以席藻为主,小球藻、色球藻在少数点位形成一定的优势。根据生物多样性指数H与均匀度指数J值等综合判断,南四湖为中-富营养型水体。

To understand the community characteristics of phytoplankton in Lake Nansi, four times surveys at 15 sites were conducted in March, June, September and November in 2010. 117 species of 8 phyla were identified. The density of phytoplankton was ranging from 33×104 ind./L to 2434×104 ind./L with the mean value being 548×104 ind./L . The biomass was 0.46 mg/L ？25.9 mg/L with the mean value of 6.45 mg/L. The Shannon-Wiener index varied from 0.84 to 2.68 with an mean value of 1.76 with the order as follow： March〉June〉November〉September. The dominant species consisted of 2 kinds of cyanobacteria, 2 kinds of bacillariophyta, 1 kind of chlorophyta and 1 kind of cryptophyta with chlorella and chroococcus being the dominant species in spring, Phormidium in autumn and winter while chlorella and chroococcus being dominant species at some sites. According to evaluation of Shannon-Wiener index and Simpson index, Lake Nansi has been in the state of middle-eutrophic.