仙女湖及入湖河流浮游植物功能类群与环境因子的相互关系

文章分析了仙女湖及入湖河流浮游植物群落结构和功能类群的时空分布特征, 探讨了影响其时空分布规律的关键环境因子。调查期间共鉴定表层水体中浮游植物82种(属), 包括蓝藻15种(属), 绿藻33种(属), 硅藻23种(属), 甲藻3种(属), 裸藻5种(属), 隐藻2种(属), 金藻1种(属)。各季节平均密度和生物量分别在7.95×106—2.19×109 cells/L和10.52—792.91 mg/L变化。群落功能类群的结果表明, 冬、春河流生境中具硅质结构的无鞭毛个体浮游植物(硅藻门)占据主导地位(Ⅵ功能群), 而湖区生境中具鞭毛、中等到大型的单细胞或群体浮游植物(如隐藻和甲藻)具有明显优势(Ⅴ功能群); 而夏秋季节不同生境中虽然Ⅵ型浮游植物数量仍然相对较高, 但是具伪空胞的、较大表面积/体积比的丝状个体浮游植物(Ⅲ型)以及具胶质鞘、小的表面积/体积比的群体类的浮游植物(如蓝藻, Ⅶ功能群)在某些河流和湖泊生境中的比重有显著增长。功能类群与环境因子的相关分析表明: 冬、春季Ⅴ与Ⅵ功能群浮游植物生物量主要受到总氮和总磷水平影响; 而夏、秋季节Ⅲ与Ⅶ功能群浮游植物受到水温、浊度、总氮和总磷水平的多重影响。

RELATIONSHIP BETWEEN PHYTOPLANKTON MORPHOLOGY-BASED FUNCTIONAL GROUPS AND ENVIRONMENTAL FACTORS OF DIFFERENT HABITAT IN THE LAKE XIANNü AND INFLOW RIVERS

Phytoplankton is an essential component for the functioning of material cycle and energy flow which accounts for half of earth’s primary production. Meanwhile, phytoplankton community structure and distribution are important indicators of water environment and its quality. Identifying the main factors driving phytoplankton community structure is essential for better understanding and therefore managing freshwater ecosystem. Hence, we investigated phytoplankton community structure, morphology-based functional groups and temporal and spatial distribution of these groups among Lake Xiannü and inflow rivers during 2014—2015. There were 82 species of 7 phyla recorded, including 15 species of Cyanophyta, 33 species of Chlorophyta, 23 species of Bacillariophyta, 3 species of Pyrrophyta, 5 species of Euglenophyta, 2 species of Cryptophyta and 1 species of Chrysophyta. The average phytoplankton density and biomass were in ranges of 7.95×106—2.19×109 ind./L and 10.52—792.91 mg/L, respectively. Non-flagellated, with siliceous exoskeletons phytoplankton (Group Ⅵ, diatom) was the dominant species in river habitat in spring and autumn. Unicellular flagellates of medium to large phytoplankton (Group Ⅴ, Cryptophyta and Pyrrophta) was the dominant species in lake zones. Although biomass of Group Ⅵ phytoplankton was relatively high in different habitats, large filaments with aerotopes phytoplankton (Group Ⅲ) and large mucilaginous colonies (Group Ⅶ), such as Cyanophyta, increased significantly between summer and autumn. Analysis of the relationship between phytoplankton morphology-based functional groups and environmental factors found that the biomass of Group Ⅴ and Ⅵ was affected by the TN and TP concentration in winter and spring. In summer and autumn, phytoplankton of Group Ⅲ and Ⅶ were affected by multiple factors including water temperature, turbidity and TN and TP concentrations.