中文摘要：

基于溧阳市天目湖沙河水库2009—2014年的硅藻群落结构及水质调查,以及宜兴横山水库等硅藻水华期藻类和水质调查数据,分析了太湖流域水库中硅藻水华群落结构特征及受气温、水位、营养盐等环境条件的影响.结果表明,太湖流域硅藻水华的主要发生期为5—7月,快速生长期发生在气温为16-26℃期间,当气温超过26℃时,硅藻的生物量开始下降.硅藻的优势属包括针杆藻、曲壳藻、小环藻和颗粒直链藻.其中沙河水库和横山水库中针杆藻是主要危害,其生物量主导了硅藻总生物量.大溪水库有时以针杆藻为主,有时以颗粒直链藻为主.当总氮浓度低于1.0 mg/L的Ⅲ类水上限时,水体氮浓度能大大限制硅藻生物量,当总磷浓度低于0.025 mg/L的Ⅱ类水上限时,也可能对硅藻生物量产生限制.高于此营养水平,硅藻水华的严重程度主要受气温、降雨等因素影响.研究表明,对于处于中营养水平的太湖流域水库而言,硅藻生物量既受气温、降雨、水位等气象水文条件的控制,又受氮、磷、硅等营养盐供给的影响.硅藻水华的防控既要关注气候和气象条件,也要尽量削减氮、磷营养盐入湖通量,维持较低营养盐水平是确保硅藻水华不形成危害的关键.

英文摘要：

Based on monthly investigation of diatom community and the related environmental conditions during six years in Shahe Reservoir,Lake Tianmu,Liyang City,and investigation of the bloom seasons in Hengshan Reservoir,Yixing City,the environmental and biological characteristics of diatom bloom in reservoirs of Taihu Basin has been analyzed. It was shown that the diatom bloom season in these reservoirs normally happened from May to July. The diatom biomass started to increase significantly when air temperature was above 16℃,and reached the highest growth rate when air temperature was 26℃. The predominant genera of diatom in these reservoirs were Synedra,Achnanthes,Cyclotella and Melocira. Synedra was the dominant species in the diatom community. Being meso-trophic condition in most of these reservoirs,both climate condition and high nutrient level were important to cause diatom blooms. What total nitrogen is lower than 1. 0 mg / L or total phosphorus is lower than 0. 025 mg / L can create the limitation effect on the diatom biomass in these reservoirs. When the nutrient concentration is higher than those levels,climate condition will be significantly control to make the severity of diatom bloom in the reservoirs.