摘 要 I 摘 要 巢湖是重要的淡水资源和具有重要功能的生态系统，但富营养化问题严重，水 体中充足的营养盐会造成浮游藻类的大量繁殖，严重时能引起―水华‖的发生叶绿 素a是浮游植物现存量的重要指标,是研究水体富营养化的主要手段和指标 因此, 叶 绿素a 常作为湖泊富营养化调查的一个主要参数 本研究在巢湖确定了 23 个采样点，分别在 2007 年的 6、7、8、9、10 月份进 行采样调查主要测定了水温、pH、溶解氧等物理指标；总氮、总磷、活性磷等化 学指标；对浮游植物的种类组成、叶绿素浓度进行了测定和分析，并结合环境因子， 探讨了巢湖蓝藻表面水华形成的环境条件结果表明： 1、TN和TP变化范围分别在0.4～3.44mg/L、0.016～0.662mg/L之间，东西湖区 水质状况明显不同，西部湖区比东部湖区水质更为严重巢湖的西部湖区水体中溶 解性磷已经达到0.011－0.41mg/L，推测在西半湖氮、磷可能已经不再是藻类生长的 主要限制因子 2、研究期间，总藻类叶绿素最大值(30.27μg/L)出现在6月，最小值(16.29 μg/L) 出现在10月 绿藻和硅藻的生物量最大值出现在7月， 与之相反蓝藻的最小值出现在 7月份。
蓝藻为最重要的藻类类群(平均值占总藻类生物量的63.36%)，在夏季和秋季 占优势；其次为隐藻 (平均值占16%)；绿藻(年平均值占15.2%)在仲夏7月较为丰富 相关性分析结果表明，两湖区的藻类生长均与磷元素和pH显著相关叶绿素a含量 与TN浓度的关系存在空间差异西半湖叶绿素含量与总氮显著正相关，与电导率、 DO呈正相关，与温度无关东半湖叶绿素含量与DO和pH显著正相关，与水温、总 氮呈正相关；全湖叶绿素含量与温度、DO、电导率、总磷、总氮等显著相关各种 生态因子对叶绿素a含量有着直接和间接的影响， 不同湖区各影响因子所起的作用不 同 巢湖水体中的叶绿素a和众多环境因子表现出多元相关性， 表明水体中浮游植物 的生长繁殖是众多水质因子综合作用的结果 3、 藻类相关性分析显示， 蓝藻与绿藻、 硅藻的含量之间存在呈显著的负相关性， 与总叶绿素a含量之间存在呈显著的相关性一般情况下，在同一垂直深度，当蓝藻 叶绿素浓度达到一定值(40µ gChlA/l左右)时， 绿藻和硅藻的生物量近乎为零， 蓝藻占 有绝对优势； 当蓝藻叶绿素浓度低于一定值(30µ gChlA/l左右)时， 绿藻和硅藻出现一 定的生物量。
研究期间，巢湖浮游植物无分层现象研究结果显示，在蓝藻水华大 安徽大学生命科学学院硕士学位论文•缪灿•巢湖夏秋季浮游植物叶绿素 a 及蓝藻水华影响因素分析 II 面积发生前后，叶绿素的浓度维持在一个较高的水平（10mg/m3），暗示着水体中 已经存在较大的藻类生物量，有再次大面积形成水华的能力，推测蓝藻表面水华形 成只是水体中已经存在大量蓝藻的结果，而并非蓝藻量突然增多的标志 4、水温、光照和营养盐浓度等是控制浮游植物种类季节动态的几个关键因素 国内外许多研究表明，水文气象因子对湖泊富营养化和蓝藻水华暴发具有很重要的 驱动作用初步认为巢湖蓝藻暴发的气象条件包括以下三个方面：1、气温适宜 (22~30℃) 2、风速较小；3、中等强度日照巢湖蓝藻水华以中轻度暴发为主，主要 出现在5－11月，其中秋季最易暴发，西半湖蓝藻暴发频次多于东半湖研究表明， 当前巢湖的水体中氮磷等营养物质已经具备了蓝藻大量繁殖的条件，我们推测如果 蓝藻越冬及春季复苏情况正常，在水文气象因素适宜的情况下，会有大面积暴发的 可能 关键词: 巢湖 叶绿素a浓度 浮游植物 蓝藻水华 富营养化 ABSTRACT III ABSTRACT Lake Chaohu is a kind of important fresh water resources, which undertake some crucial ecological functions. But eutrophication of the lake water has been very serious.Excessive nutrients in eutrophic water may make phytoplanktons propagate and water quality worsen, sometimes even arise algae bloom. Chlorophyll a is an important means and index for researching and evaluating eutrophication. Therefore, chlorophyll a often as one of the main parameters in survey of the lake eutrophication. There are 23 sampling sites in Lake Chaohu,8 sampling sites in the western part of the lake,15 sampling sites in the eastern part. Carried on researches at 6, 7, 9，10 of 2007 respectively. Determined physical indexes such as water temperature(WT), PH, dissolved oxygen (DO) and chemical indexes for instance total nitrogens (TN), total phosphorus (TP), orthophosphate(P04-P); appraised phytoplankton species complexity and chlorophyll concentration. The result demonstrated that： 1.The TN and TP concentrations change from 0.4 mg/L to 3.44mg/L,and 0.016 mg/L to 0.662mg/L, TN and TP concentrations were higher in the western than in the eastern areas. The soluble phosphorus concentrations of the western areas achieved 0.011-0.41mg/L already. We extrapolated that phosphorus was possibly not the dominant nutrient,which limits the growth of algae in the western areas of Lake Chaohu. 2.On the average of the whole lake, total algal biomass reached the maximum in June (30.27μg/L)and the minimum in October (16.29 μg/L). Chlorophyta and Bacillariophyta biomass reached the maximum in July，the Cyanobacterial biomass reached the minimum in July by contraries.In terms of annual mean biomass, cyanobacteria comprised 63.36% of total algal biomass, followed by Cryptophyta (16%) and Chlorophyta (15.2%). Through relevant analysis，it was found that the growth of algae had significant correlation with phosphorus element and pH.The relationships between Chl-a content and TN concentrations were different in the different monitoring zones. In the western part of the lake, there was significant correlation between chlorophyll-a concentration and TN concentration,and correlation between total chlorophyll-a concentration and conductance and dissolved oxygen (DO),and no 安徽大学生命科学学院硕士学位论文•缪灿•巢湖夏秋季浮游植物叶绿素 a 及蓝藻水华影响因素分析 IV correlation between chlorophyll-a concentration and water temperature.In the eastern part of the lake, there was significant correlation between chlorophyll-a concentration and dissolved oxygen (DO) and pH,and correlation between chlorophyll-a concentration and TN concentration and water temperature. chlorophyll-a concentration had significant correlation with temperature, DO, conductivity, TP and TN.Ecological factors had significant impact on the concentrations of chlorophyll-a directly and indirectly. However, the main factors were different in different regions of Lake Chaohu. Chlorophyll-a can be regressed linearly to these factors，which suggested that the growth and development of phytoplankton in Chaohu lake is the overal1 effects of these factors. 3.There was significant negative correlation between cyanobacterial biomass and Chlorophyta and Bacillariophyta,and significant correlation with chlorophyll concentration.Commonly, in identical depth when Cyanobacterial chlorophyll concentration achieves a value (about 40 μgChlA/L), Chlorophyta and Bacillariophyta biomass approach zero. When Cyanobacterial chlorophyl。