【作者】 吴凯；

【导师】 李正魁；

【作者基本信息】 南京大学 ， 环境工程， 2011， 硕士

【摘要】 近年来,太湖蓝藻水华暴发受到人们广泛的关注,其暴发机理也成为环境界研究的热点。其中上浮是蓝藻水华暴发的关键阶段,如果将上浮机理研究清楚,则可以有效地控制蓝藻水华的暴发,从而缓解饮水危机。因此,研究蓝藻上浮特别是微囊藻的浮力调控和垂直迁移特征对于揭示蓝藻水华形成机制,了解蓝藻水华的诱发机理具有十分重要的意义。本论文在国家重点基础研究发展计划(973计划)“大中型浅水湖泊蓝藻水华暴发机理研究”项目第三课题“水华蓝藻原位生长和输移聚集的全湖过程与驱动机制”(编号：2008CB418003)资助下,通过原位监测和室内实验相结合的方法,研究了温度、pH、特征污染物等因子对表层水华形成的影响,考察了物化因子驱动蓝藻水华在水柱中上浮的综合效应,分析了蓝藻水华上浮规律；探讨了蓝藻水华上浮的主要驱动因子,试图揭示蓝藻水华形成和输移规律。原位监测主要研究了太湖的物理化学因素和太湖水华现状特征和蓝藻上浮特征,室内模拟采用柱状中试反应装置模拟了蓝藻上浮过程,探讨了物理化学因素与水华蓝藻上浮调控的相互作用,以期为揭示大中型浅水湖泊太湖蓝藻水华暴发的生物学和生态学综合机理和为蓝藻水华暴发的预测预警奠定科学基础,以及为建立蓝藻水华综合防治的生态技术原理体系,提出蓝藻水华预防与控制的战略对策,为实现我国水生态安全战略提供坚实的科学依据。本论文主要研究结论如下：(1)太湖水华优势藻种以蓝藻为主,优势种属为微囊藻(microcystis),水华暴发季节生物量可达到1.35×108个·L-1,此外水体中还存在绿藻、硅藻和隐藻等,蓝藻和绿藻之间存在竞争关系；(2)春季太湖水体中硝态氮、氨氮、总氮都达到最大值,而总磷、正磷酸盐和氮磷比的变化趋势不明显,RDA分析发现总氮对蓝藻的生长影响大于总磷的影响,蓝藻生物量与总氮总磷、DIN/SRP和亚硝态氮具有显著的相关性,应该同时控制氮磷,尤其是溶解性无机氮DIN和活性磷SRP,为蓝藻水华的控制提供了一定的科学依据；(3)原位蓝藻上浮率与化学因素没有显著相关性,分析原因可能是原位水华蓝藻的生境比较复杂,影响因素比较多,除了受到化学因素的关系外,可能还受到其他水力条件的影响；(4)反应器表层蓝藻上浮率明显大于底部,表层以下上浮率随时间没有明显变化规律,在不同时刻上浮率变化特征是r22：00>r10：00>r14：00；(5)pH和正磷酸盐变化特征是表层和底层的值大于中间,原位蓝藻对正磷酸盐表现出很强的吸收能力；(6)碳水化合物、氨氮、DO是影响反应器内蓝藻上浮的主要物理化学因素,蓝藻可能主要通过改变细胞内镇重物的含量和通过合成伪空泡来调节其上浮。更多还原

【Abstract】 In recent years, outbreaks of algae-blooms in Taihu Lake cause wide attention, and the outbreak mechanism become focus of environmental study. Floating is the critical stage about algae bloom, if understand the floating mechanism, we can effectively control the outbreak of algae-bloom and ease the water crisis. It has great significance in studying water-blooms formatting mechanism, especially microcystis buoyancy regulation and vertical migration characteristics and mechanism induced algal blooms.In order to reveal the integrated biology and ecology mechanism about outbreak of algal blooms in shallow and medium-sized Taihu Lake, and to provide scientific basis in predicting algal bloom; As well as to establish technical principles of ecological system in controlling algal blooms, and to propose strategic prevention about cyanobacteria bloom and to provide a solid scientific basis for the realization of water ecological safety, temperature, pH, characteristics of surface water pollution and other factors about water-blooms formation were studied by in-situ monitoring and laboratory experiments, and combined effect about physical and chemical factors driving algal blooms floating in the water column were clarified, and the laws of floating algal blooms were revealed; the main driving factors of floating algal blooms were analysised, and the formation of algal blooms and transport law were revealed. In situ monitoring key physical and chemical factors in the Taihu Lake and algae blooms floating status characteristics were studied, laboratory simulation by using cylindrical reactor to simulate the process of algae floating, of the physical chemistry and the interaction of floating algae blooms, and interactions between floating algae bloom and the chemical and physical factors were explored, basing on the third topic "The whole lake process and the driving mechanism of algae growth and transport" of the national key basic research and development program "973"(No:2008CB418003).The main conclusions are as follows:(1) Dominant species was cymobacteria(microcystis) in Taihu Lake, and seasonal water bloom biomass reached 1.35×108 cells-L-1, there were also green algae, diatoms and hidden algae, competition existed between cyanobacteria and green algae;(2) In spring nitrate nitrogen, ammonia nitrogen, total nitrogen up to the maximal concentration, however total phosphorus, orthophosphate concentration and N/P varied indistinctively. (Representational difference analysis) RDA analysis expresses that effects of TN is bigger than TP on growth of microcystis; Remarkable correlation exists between TN, TP, DIN/SRP, NO2-N and biomass of microcystis. It should also simultaneously control nitrogen and phosphorus, particularly control DIN and SRP to control the blooms, it provides some scientific evidences in controlling water bloom;(3) There is no significant correlation between situ chemical factors and algae floating rate, the reason may be complex situ habitat and more complex factors. In addition to chemical factors, other hydraulic condition maybe affect algae floating rate;(4) Floating rate in the surface was significantly higher than it in the bottom, and in the day it is lower than that in the night, r22:00>r10:00>r14:00;(5) Changes about pH and phosphate were similar to the law that their values emerged in the surface and bottom was less than that in the middle;(6) Correlation analysis showed that carbohydrates, ammonia and dissolved oxygen were the main factors affecting algae floating in reactor, cyanobacteria adjust its float maybe by changing the carbohydrate concentration in cells and controlling synthesis of pseudo-bubble.更多还原