【作者】 肖利娟；

【导师】 韩博平；

【作者基本信息】 暨南大学 ， 水生生物学， 2011， 博士

【摘要】 为了解华南地区大型水库的浮游植物演替机制,本文于2008年1月-2010年12月对流溪河水库和2008年8月-2010年12月对大沙河水库的浮游植物群落结构及其环境因子分别进行采样调查。分析两座水库的湖沼学变量特征、浮游植物生物量、浮游植物群落和功能类群演替过程。应用多元统计分析方法,对浮游植物群落和环境因子进行CCA和RDA排序,分别提取出两座水库中影响浮游植物群落结构的主要环境因子和驱动浮游植物群落演替的关键因素；应用相关分析和回归分析提取出影响大沙河水库主要优势蓝藻(微囊藻和卷曲鱼腥藻)种群动态的关键变量。主要研究结果如下：1、受夏季风的影响,华南地区的降雨集中而强烈,这一过程与人为用水的调节作用共同导致两座水库水位波动和水体滞留时间的季节性变化。受水库形态的影响,两座水库的水动力学特征和水体温度结构的差异较大,同时两座水库中水位波动、滞留时间和水体混合状况对水体营养盐和光的可获得性的作用有较大差异。在流溪河水库水位变化是导致透明度和营养盐变化的主要原因,而在大沙河水库水体混合是影响水体透明度和营养盐变化的主要原因。2、两座水库均为单混合型和磷限制水体,属于中长滞留型水体。水体中光的可获得性、总磷和滞留时间是决定浮游植物现存量的关键因素,但其作用的强度在水库河流区、过渡区和湖泊区的空间差异显著(p<0.05)。流溪河水库为贫中营养水体,总磷和光的可获得性是浮游植物生物量的主要决定变量；大沙河水库为中富营养水体,总磷、光的可获得性和水体滞留时间均是浮游植物生物量的决定变量。3、流溪河水库中共检到浮游植物124种隶属于27个功能类群,浮游植物群落属于甲藻-硅藻型,7-9月浮游植物群落平均细胞体积最小。流溪河水库浮游植物群落结构和功能类群组成有显著的空间差异,主要优势种有小环藻(Cyclotella spp.)、微小多甲藻(Peridin ium pusillum)、二角多甲藻(Peridinium bipes)、飞燕角甲藻(Ceratium hirundinella),多元统计分析(CCA和RDA)表明真光层深度,溶解态磷和光的可获得性是影响浮游植物群落结构和功能类群组成的主要因子。降雨和人为调水共同导致的水位变化和水体分层是驱动流溪河水库浮游植物群落季节演替的主要因素。4、大沙河水库共检到浮游植物175种,隶属于25个功能类群,浮游植物群落属于蓝藻-绿藻型,7-9月的浮游植物群落平均细胞体积最大。大沙河水库浮游植物群落结构和功能类群组成没有显著的空间差异,主要优势种有微囊藻、卷曲鱼腥藻、光角星鼓藻(Staurastrum muticum)和纤细角星鼓藻(Staurastrum gracile),多元统计分析(CCA和RDA)表明总氮、水位、氨氮、pH值和水体滞留时间是影响浮游植物群落结构的主要因子,但真光层深度为决定浮游植物功能类群组成的主要因子。降雨和人为调水共同导致的水体滞留时间变化和水体分层是驱动大沙河水库浮游植物群落季节演替的主要因素。5、微囊藻和卷曲鱼腥藻是大沙河水库主要的优势蓝藻,两种藻类的生物量高峰值在时间上不重叠。微囊藻的生态宽幅为2.1,为S-策略种,较高生物量和优势度出现在10-4月,其生物量与温度、真光层深度和真光层深度/混合层深度之比有显著负相关性,与总氮、总磷、氨氮、硝氮和水体滞留时间有显著正相关；卷曲鱼腥藻的生态宽幅为1.7,为S-C策略之间的种类,较高生物量和优势度的发生没有明显的季节性,其生物量与水体滞留时间有显著正相关性。更多还原

【Abstract】 To understand the succession of phytoplankton communities in reservoir in southern China, phytoplankton assemblages and environmental factors were investigated from January,2008 to December,2010 in Liuxihe reservoir and August,2008 to December,2010 in Dashahe reservoir. Limnological features, phytoplankton biomass and community structure and phytoplankton functional groups structure in the two reservoirs were comparatively explored. Multivariate analysis (CCA and RDA) was used to analyze the correlations between phytoplankton assemblages and environmental factors. Correlation and regression analysis were used to identify critical factors regulating the population dynamics of Microcystis and Anabaena circinalis.Both the intensive monsoon rains and artificial drawdown lead to the seasonality of water level and water retention time. Basin morphology influences hydrodynamics, temperature structure in water column and the effect of water level, water retention time and mixing regime on the availability of nutrients and light in the two reservoirs. Water level was the primary factor regulating nutrient and light availability in Liuxihe reservoir, while mixing regime was the primary factor that influenced nutrients and light availability in Dashahe reservoir.Availability of light, phosphorus and water retention time were the primary factors determining the phytoplankton standing biomass, but their roles significantly different between the riverine, transition, and lacustrine zones. Liuxihe reservoir was oligo-mesotrophic, and phosphorus concentration and availability of light were the most important factors for phytoplankton standing biomass. Dashahe reservoir was meso-eutrophic, and phosphorus concentration, availability of light and water retention time were all important for phytoplankton standing biomass.One hundred and twenty four species and 27 phytoplankton functional groups were identified in Liuxihe reservoir. The phytoplankton with smaller biovolume was predominant from July to September. The assemblage was dominated by Dinophyta and Bacillariophyta and showed a spatial difference in structure. Cyclotella spp., Peridinium pusillum, Peridinium bipes, Ceratium hirundinella were the primary predominant species. Multiple analyses indicated that euphotic depth, dissolved phosphorus concentration and light availability were the first important factors for structuring phytoplankton assemblage and functional groups. Water level controlled by monsoon rains and artificial drawdown and nutrient and light availability regulated by water stratification were the primary driven factors for phytoplankton community seasonal succession in Liuxihe reservoir.One hundred and seventy five species and 25 phytoplankton functional groups were identified in Dashahe reservoir. A phytoplankton with larger biovolume was predominant from July to September. The assemblage was dominated by Cyanophyta and Chlorophyta without markedly spatial difference in structure. Microcystis spp., Anabaena circinalis, Staurastrum muticum, Staurastrum gracile became the predominant species. Multiple analyses showed that total nitrogen, water level, ammonium, pH and water retention time were important for structuring phytoplankton assemblage, but euphotic depth was the critical factor for structuring phytoplankton functional groups. Water retention time was mainly controlled by monsoon rains and artificial drawdown, it affected phytoplankton growth rate. Water stratification altered nutrient availability. Water retention time and water stratification were the primary driven factors for seasonal succession of phytoplankton community in Dashahe reservoir.5) Microcystis and Anabaena circinalis were the prevailing cyanobacteria in Dashahe reservoir, and their biomass peaks separate seasonally. Microcystis with S-life strategy has a broader niche than Anabaena circinalis. Microcystis biomass significantly negatively correlated with water temperature, euphotic depth, the ratio of euphotic depth and mixing depth but positively correlated with total nitrogen, total phosphorus, ammonium, nitrate and water retention time. Anabaena circinalis has a life strategy in the intergradation zone of a S-C strategy and its biomass was significantly positively correlated with water retention time.更多还原