南四湖浮游植物种群构成特征及季节变化

浮游植物是评价水体质量的一项重要生物指标,2008-06～2009-05在南四湖设置5个监测点,每月采样一次,对浮游植物种群组成、密度和优势种变化进行了系统研究。结果表明:南四湖共检出浮游植物8门59属117种;绿藻、硅藻分别占浮游植物总种数的48.7%、23.9%;浮游植物种数夏秋季节多,冬春季节少;浮游植物密度与种数季节变化一致。南四湖浮游植物优势度指数变化范围为0.04～0.35,优势种种数较多,主要有小球藻(Chlorella vulgaris)、二形栅藻(Scenedesmus dimorphus)、颗粒直链藻(Aulacoseira granulata)等23种。南四湖浮游植物多样性指数和均匀度指数变化范围分别为1.56～2.36、0.59～0.84,表明南四湖水体中浮游植物群落结构较复杂。南四湖浮游植物种群特征较20世纪80年代发生了明显变化。

Population characteristics and seasonal variations of phytoplankton in Nansi Lake

Phytoplankton are an important biological indicator for water quality assessment. To investigate the water quality of Nansi Lake, the population composition, quantity and dominant species of phytoplankton were studied from June 2008 to May 2009. 8 phyla, 59 genera and 117 species have been identified from 5 monitoring stations based on a monthly sampling. The species numbers of Chlorophyta and Bacillariophyta accounted for the total species number were 48.7％ and 23.9％, respectively. There were many more species in summer and autumn than that in winter and spring. The seasonal variations of phytoplankton density were the same as that of species number. The predominant indices were not high, ranging from 0.04 to 0.35, and there were 23 predominant species including Chlorella vulgaris, Scenedesmus dimorphus and  Aulacoseira granulata. The phytoplankton diversity and evenness indices varied from 1.56 to 2.36, and 0.59 to 0.84, respectively. It could be concluded that the phytoplankton population structure in Nansi Lake is complex, and the stability of the phytoplankton population composition and quantitative distribution showed a high degree in Nansi Lake. The phytoplankton population characteristics changed significantly compared with the data in 1980s.