乌梁素海春季浮游植物群落结构特征分析

寒区湿地经过冬季冰封期后，春季浮游植物群落结构特征对湿地生态环境质量有一定的指示性作用。对乌梁素海2012年5月浮游植物群落调查分析的结果表明，乌梁素海春季浮游植物共有7门59属96种，其中绿藻种类最多为29属54种，占56.25％，其次为硅藻11属18种，占18.75％；湖区优势种为湖生束球藻、色球藻、卵囊藻、四尾栅藻、小球藻、胶网藻以及梅尼小环藻；浮游植物平均密度为8.895×107 cell·L-1,且空间分布极不均匀，变异系数为0.94，Shannon-Wiener指数为1.34~2.66，Pielou指数为0.30~0.52。结合浮游植物密度、优势种及多样性指数等结果，乌梁素海属于绿藻-蓝藻-硅藻型，且水体已处于富营养化状态。聚类和多维尺度分析显示：春季乌梁素海浮游植物群落可分为进水流水型群落、南部深度净化型群落、北部沿岸静水型群落及中部滞留型群落。

Structural Characteristics of Phytoplankton Community in the Spring in Wuliangsuhai Lake, China

After the period of frozen in the winter, the community structure of phytoplankton in spring may indicate the environment quality of wetlands to some extent in the cold region. The community structure of phytoplankton in Wuliangsuhai in May of 2012 was analyzed. The results showed that there were 59 genera, 7 phyla and 96 species of phytoplankton with dominated chlorophyta including 54 species of 29 genera accounting for 56.25% of the whole phytoplankton at Wuliangsuhai. We also found 11 genera and 18 species of bacillariophyta accounting for 18.75% of phytoplankton. The dominant species were Gomphosphaeria lacustris, Chroococcus, Oocystis, Scenedesmus quadricauda, Chlorella vulgaris, Dictyosphaerium pulchellum, Cyclotella meneghiniana. The average density of phytoplankton was 8.895×107 cell·L-1. The phytoplankton abundance was unevenly spatially-distributed with a variation coefficient of 0.94. The phytoplankton Shannon index was 1.34 to 2.66 and Pielou index varied from 0.30 to 0.52. Based on the information about the abundance of phytoplankton, the index of dominant species, and the index of diversity suggests that Wuliangsuhai has been eutrophicated dominated with Cyanophyta, Chlorophyta and Bacillariophyta. Clustering and multi-dimensional scaling analysis showed that phytoplankton community could be classified as the influent community in the north, deep purification community in the south, hydrostatic community in the north along the coast, retention community in the central part of the lake in spring.