江湖连通调控引水的季节性生态效应研究

Seasonal effect on algae ecosystem structure of water diversion from river to lake is remarkable. In some months, it can reduce the dominance of blue algae, while it can bring large amount of nitrogen and phosphorus into lake but can not reduce blue aglae. Field survey, algae culturing in experimental pond and numerical simulation method is planned to adopted in the proposal.The advanced phytoplankton analyzer system PHYTO-PAM is also planned to determine the content of active chlorophyll a for different algae kinds such as blue, green algae and diatoms and total active chlorophyll a for all kinds of algae.Furthermore, the photosynthetic performance and light-adaptational state of the various types of algae can be assessed with the system.Hydrological and weather factors, physical and chemical factors of natural water in the accepted region for water diversion from Yangtze river to Lake Taihu will be surveyed and simulated by numerical models. The data and simulated results will be combined with the ecological and biological indexes in order to analysize the mixing success of Yantze river water and local lake water, and also the effects of water diversion on water ecosystem structure and its environmental factors which governing its behaviors in different seasons.The relationship between the biomass productivity of algae and hydological and weather factors, phyical and chemical factors will be analyzed by measuring the photosynthetic performance of algae and competance of each other. The seasonal adaptation to the water diversion for the algae ecosystem in different seasons will be clearing explaned at the end of this study.A seasonal ecosystem suitable propose for water diversion from Yangtze river to Lake Taihu will be proposed at last.

江湖连通调控工程引水对受水湖区藻类种群结构的影响具有鲜明的季节性生态效应，在某些月份引水能较好地抑制蓝藻竞争优势，但某些月份可能作用不大而引入大量氮.本研究课题拟以野外观测、试验池对比培养实验和数值模拟相结合的方法，采用先进的调制荧光仪PHYTO-PAM测定蓝藻、硅藻、绿藻门叶绿素a含量、总叶绿素a含量以及各门藻的生物光合作用效率和光合潜能，并与江湖联通调控引水过程中水文、气象、受水湖区水体理化要素的观测数据和数值模拟结果进行相关分析，研究长江水源客水与太湖本地水源的同化过程，长江水源客水对受纳水体生态系统环境要素的影响以及环境要素的改变对本地藻类生态系统群落结构的影响过程，揭示光合作用效率和光合潜能指标分析蓝藻竞争能力与水文、气象、受水湖区水体理化要素的相关关系，阐明不同季节引水对受水湖区的生态环境要素的影响及生态系统的季节适应性，从而提出生态适宜的季节性引水条件。

河湖连通调控引水的季节性生态效应是科学指导引水策略的重要依据。本课题采用数值模拟、野外观测和试验以及室内实验等方法，详细研究了长江客水与太湖本地水的同化过程及对太湖受纳水体硅酸盐、TN、TP、水下光谱等生态系统环境要素的影响。试验分析了长江水在不同季节对蓝藻、硅藻、绿藻门叶绿素a 最大光合潜能的影响规律，初步揭示了不同季节引水的生态环境效应以及藻类生态系统结构、生存环境的季节性变化效应。筛选出了调水引流蓝藻环境敏感影响因子悬浮泥沙和硅酸盐，从而提出了太湖抑制局部湖湾蓝藻生长的季节性引水策略建议。