红水河干流梯级水库秋季浮游植物群落结构特征与水质评价

Community Structure Characteristics of Phytoplankton and Water Quality Assessment in Cascade Reservoirs in Hongshui River Drainage in Autumn

2010年秋季调查了红水河干流六座梯级水库（龙滩水库、岩滩水库、大化水库、百龙滩水库、乐滩水库和桥巩水库）浮游植物的种类组成、密度、生物量和分布情况。共鉴定浮游植物6门64种,其中硅藻31种、绿藻17种、蓝藻10种、甲藻2种、金藻2种、红藻2种。优势度分析显示：各梯级水库浮游植物优势种均以硅藻为主,其次为绿藻和蓝藻。红水河流域各梯级水库浮游植物密度变化在3.41×105~5.90×105个/L之间,其中百龙滩水库最高,桥巩水库最低。浮游植物生物量变化在0.55~2.70mg/L之间,龙滩水库最高,大化水库最低。Shannon-Wiener多样性指数在2.03~2.88之间。均匀度指数在0.52~0.95之间。各梯级水库浮游植物组成相似性系数变化在0.34~0.72之间,大化水库和百龙滩水库浮游植物组成的相似性最小（0.34）,龙滩水库和桥巩水库相似性最大（0.72）。综合多种指标显示：龙滩水库水质为贫-中营养型,岩滩水库、大化水库、百龙滩水库、乐滩水库,及桥巩水库水质均为贫营养型。

Species composition, density and biomass, spatial distribution and biodiversity of phytoplankton were investigated in six cascade reservoirs in Hongshui River, including Longtan Reservoir, Yantan Reservoir, Dahua Reservoir, Bailongtan Reservoir, Letan Reservoir and Qiaogong Reservoir in autumn in 2010. In total, 64 species algae, being classified into 6 phyla, were identified in taxonomy. The results showed that species in Bacillariophyta were dominated in the phytoplankton community, followed by members in Chlorophyta and Cyanophyta. There were 31 species（accounting for 48.44%） in Bacillariophyta, 17 species representing 26.56% in Chlorophyta and 10 species（accounting for 15.63%） in Cyanophyta. Also, 2 species in Pyrrophyta, 2 species in Chrysophyta and 2species in Rhodophyta were observed, accounting for 3.13% for each. The dominance index analysis revealed that members in Bacillariophyta were found to be the dominant phytoplankton species in the six cascade reservoirs in Hongshui River, followed by species in Chlorophyta and Cyanophyta. The phytoplankton density in each cascade reservoir was ranged from 3.41×105ind./L to 5.90×105ind./L, with the maximal density of 5.90 ×105ind./L in Bailongtan Reservoir, and the minimum of 3.41 ×105ind./L in Qiaogong Reservoir. The phytoplankton biomass in each cascade reservoir was varied from 0.55 mg/L to 2.70 mg/L, with the maximum of 2.70 mg/L in Longtan Reservoir and the minimum of 0.55 mg/L in Dahua Reservoir, with Shannon-Wiener diversity index from 2.03 to 2.88, and Pielou evenness index from 0.52 to 0.95. The similarity index of phytoplankton composition was ranged from 0.34 to 0.72, with the minimum in Dahua Reservoir and Bailongtan Reservoir, and the maximum in between Longtan Reservoir and Qiaogong Reservoir.The water quality was shown to be mesotrophic-oligotrophic in Logntan Reservoir and oligotrophic in other five reservoirs according to the evaluation standards of algal biological index.