广东南水水库富营养化与浮游植物群落动态

南水水库是广东省第三大水库,属饮用水源一级保护区。于2011年1~12月对该水库的水文、水质和浮游植物进行了每月一次、为期一年的调查,采用营养状态指数(TSI)进行了水质综合评价,分析了浮游植物群落的动态变化规律,选择冗余分析(RDA)研究了影响浮游植物群落结构的环境因素。结果表明:南水水库现为贫营养型,全年浮游植物的种类变化不大,共鉴定出浮游植物6门50属(种),优势种以适应贫营养的种类为主,且浮游植物的丰度、生物量及叶绿素a浓度都较低,其均值分别为8.72×104～2.51×105cells/L、0.031～0.423 mg/L和0.83～2.80 mg/L。浮游植物群落主要以硅藻、甲藻和绿藻种群为主,硅藻种群全年占优势,甲藻和绿藻在不同季节优势度有变化,体现出从硅藻型到硅藻-甲藻型,到硅藻-绿藻型,再到硅藻-甲藻型的变化过程。温度、氮磷比和水体稳定性的季节变化是影响上述浮游植物群落动态的主要因子。

Eutrophication and Dynamics of Phytoplankton Community in Nanshui Reservoir in Guangdong Province,China

Nanshui Reservoir is the third largest reservoir in Guangdong Province,which has been classified as a protection zone for first-grade drinking water supply.A hydrological,water quality and phytoplankton survey was conducted from January to December in 2011,with the objective to evaluate the trophic state based on trophic state index(TSI),and dynamics of phytoplankton community and associated influencing factors based on redundancy analysis(RDA).The results showed that Nanshui Reservoir was oligo-mesotrophic,with no obvious difference in phytoplankton types during the study period.A total of 50 phytoplankton genera or species were identified,which belonged to 6 phylum,and the dominant species were adapted to oligotrophic water.The abundance and biomass of phytoplanktons were in the ranges of 8.72×104~2.51×105 cells/L and 0.031~ 0.421 mg/L,whereas the concentration of chlorophyll a ranged from 0.83 to 2.80 mg/L.As far as the dynamics of phytoplankton community concerned,the phytoplankton composition was mainly dominated by Bacillariophyta,Pyrrophyta and Chlorophyta in each season,but Bacillariophyta dominated throughout the year.The specific composition of phytoplankton community displayeda seasonal pattern,from Bacillariophyta type,to Bacillariophyta-Pyrrophyta type,to Bacillariophyta-Chlorophyta type,and then to Bacillariophyta-Pyrrophyta type.Overall,the seasonal variation in temperature,concentration ratio of nitrogen and phosphorus,and water stability were the main driving factors for the dynamics of phytoplankton community in the reservoir.