湘江浮游生物资源状况的调查与分析

2009年4月至2010年11月,在不同季节对湘江流域浮游生物的资源状况进行调查。结果表明,湘江浮游植物有127种,隶属8个门,其中,绿藻门44种,硅藻门38种,蓝藻门l3种,裸藻门9种,隐藻门7种,黄藻门6种,甲藻门和金藻门各5种。浮游植物平均密度为2.91万个/L,平均生物量0.15 mg/L,其中硅藻门生物量最大,占总量的41.8%,优势种为颗粒直链藻、尖针杆藻和缘花舟形藻;浮游动物91种,其中,轮虫最多,有38种,枝角类有19种,原生动物有18种,桡足类有16种,浮游动物平均数量为13.94个/L,平均生物量为0.24 mg/L,其中桡足类生物量最大,占总量的47.7%,优势种为剑水蚤和哲水蚤。从种类组成来看,湘江浮游生物属于典型的河流型浮游生物群落结构,其种群结构特征表明湘江水体属于贫–中营养型。

Investigation and analysis of the status of plankton in Xiangjiang river

The status of plankton in Xiangjiang river was investigated in different seasons from April 2009 to November 2010. The results showed that there were 127 species of phytoplankton, belonging to 8 phyla including 44 species of Chlorophyta, 38 species of Bacillariophyta, 13 species of Cyanophyta, 9 species of Euglenophyta, 7 species of Cryptophyta, 6 species of Xanthophyta, and 5 species of Pyrrophyta and Chrysophyta respectively; the average density of phytoplankton was 2.91×104 ind/L, and the biomass was 0.15 mg/L; the biomass of the Bacillariophyta was the largest, accounting for 41.8% of the total biomass, and the predominant species were Melosira granulate, Synedra acus and Navicula radiosa. There were 91 species of zooplankton, among which 38 species belonged to Rotifera, 19 species belonged to Copepoda, 18 species belonged to Protozoa and 16 species belonged to Cladocera; the average density of zooplankton was 13.94 ind/L, and the biomass was 0.24 mg/L; the biomass of the Cladocera was the largest, accounting for 47.7% of the total biomass; Cyclops and Calanus were the predominant species appearing all over the year. The plankton in Xiangjiang river belonged to the typical river-type community structure in terms of species composition, which explained that the Xiangjiang river was in poor to moderate nutritional status.