澜沧江囊谦段夏秋季浮游植物群落结构初步研究

2011年夏季(6月)和秋季(9月)对澜沧江囊谦段的浮游植物进行初步研究。结果表明,澜沧江囊谦段浮游植物共计4门、57种(属);其中,硅藻门种类最多,为33种(属),占总种类数的57.9%;其次是绿藻门,为13种(属),占22.8%,蓝藻门10种(属),占17.5%,甲藻门仅检到1种,占1.8%。夏秋两季澜沧江囊谦段均以喜低温的硅藻为主,绿藻、蓝藻种类秋季多于夏季,甲藻仅在夏季出现。浮游植物优势种以硅藻为主,占75.0%,种类有尖针杆藻(Synedra acus)、普通等片藻(Diatoma vulgare)、舟形藻(Navicula sp.)、桥弯藻(Cymbella sp.)、曲壳藻(Achnanthes sp.)、异极藻(Gomphonem sp.)、颤藻(Oscillatoria sp.)和席藻(Phormidium sp.)。浮游植物数量为13.26×104～375.59×104个/L,平均数量99.36×104个/L;生物量为0.0445～1.9972mg/L,平均0.4915mg/L。浮游植物数量和生物量均以硅藻最高,分别占总数量的61.2%和总生物量的71.3%。分析显示,各采样点浮游植物多样性指数、均匀度指数较高,均值分别为2.24、0.48;表明该河段浮游植物群落比较稳定,种类分布较为均匀,体现了贫营养型河流的特征,水域环境良好。

Study on Community Structure of Phytoplankton in Nangqian of Lantsang River in Summer and Autumn

Phytoplankton community in Nangqian of Lantsang River was investigated in summer(June) and autumn(September) of 2011.Results showed that there 4 phyla including 57 species of phytoplankton in Nangqian of the Lantsang River in summer and autumn.Bacillariophyta were represented by the highest number of taxa(33),follwed by Chlorophyta(13),Cyanophyta(10) and Pyrrophyta(1).The kind of diatoms which like the low temperature predominated in Nangqian in Lantsang River during summer and autumn.The species number of chlorophyta and cyanophyta were higher in autumn than that in summer,while pyrrophyta was only appeared in summer.Bacillariophyta(75.0%) was dominated in phytoplankton,including Synedra acus,Diatoma vulgare,Navicula sp.,Cymbella sp.,Achnanthes sp.,Gomphonem sp.,Oscillatoria sp.and Phormidium sp..The abundance of phytoplankton ranged from 13.26 × 104 to 375.59 × 104 cells /L with the average of 99.36 × 104 cells /L,and the biomass of phytoplankton ranged from 0.0445 ～ 1.9972 mg /L with the average of 0.4915 mg /L.The abundance and biomass of diatoms were the highest in all species,occupying 61.2% and 71.3%.Shannon-Wiener index of diversity and the Pielou index of phytoplankton were much high,with the mean values of 2.24 and 0.48,respectively.These structure characteristics indicated that phytoplankton in this river was very stable and species were distributed evenly,which suggest that this river was in oligotrophic state and the aquatic environment was good.