中文摘要：

分析石臼湖江苏段浮游植物群落结构及对环境因子的响应,以期探索浅水型湖泊浮游植物动态变化机制,为石臼湖水域生态环境监测与保护、生物资源调查提供基础数据。2012年10月至2013年8月,在石臼湖江苏段12个采样点进行了4次采样,调查浮游植物的群落结构及水环境因子,并通过冗余分析（RDA）对数据进行直接梯度排序,分析浮游植物群落结构对环境因子的响应。共发现浮游植物79种,隶属于8门53属,绿藻门21属39种,蓝藻门11属13种,硅藻门10属11种1变种1变型,裸藻门4属5种,甲藻门3属4种,隐藻门2属3种,金藻门1属1种,黄藻门1属1种。优势种（属）10种,冬季以对水温和光照有较好适应能力的硅藻为主要优势种群;春季优势种类较丰富,但优势度不高（0.03～0.09）;夏、秋季节以小型丝状蓝藻占绝对优势。浮游植物总平均密度为28.93×10^6个/L,季节差异显著,峰值出现在夏季,冬季最低。多样性分析表明,石臼湖浮游植物的物种组成较丰富,然而种间分布不均,群落结构稳定性较弱。基于CANOCO的多变量分析表明：pH、溶解氧、透明度、氨氮、水温、电导率是影响浮游植物群落结构的主要环境因子。

英文摘要：

Shijiu Lake is the only riparian shallow lake connecting with the lower Yangtze River. In recent years,human activities have severely disturbed the natural environment of Shijiu Lake and concern over water quality and the aquatic ecosystem is increasing. In this study,we completed the first investigation of the phytoplankton community and primary water quality parameters in the Jiangsu Section of Shijiu Lake. After gathering data,characteristics of the phytoplankton community were analyzed and phytoplankton dynamics,in response to environmental factors,were explored. The study provides data on the aquatic environment and biological resources of Shijiu Lake and will support environmental protection. In October of 2012 and February,May and August of 2013,the phytoplankton investigation was carried out at 12 sampling sites in Shijiu Lake. The environmental parameters measured in situ included p H,dissolved oxygen（ DO）,transparency（ SD）,depth,turbidity（ Tur）,total dissolved solids,water temperature（ WT） and conductivity（ Cond）. Samples were also collected for laboratory analysis that included the5-day biological oxygen demand（ BOD5）,total nitrogen（ TN）,total phosphorus（ TP）,permanganate chemical oxygen demand（ CODMn） and ammonium nitrogen（ NH4-N）. A total of 79 phytoplankton species belonging to 8phyla and 53 genera were identified. Chlorophyta（ 39 species）,Cyanophyta（ 13 species） and Bacillariophyta（ 11species） dominated the phytoplankton community,accounting for 50. 65%,16. 88% and 14. 29% of the total species,respectively. During the investigation,10 dominant species were observed. Diatoms,adaptable to low water temperature and light intensity were the dominant phylum in winter. The dominant species were rich in spring,but the dominance values were low（ 0. 03- 0. 09）. Filamentous blue-green algae dominated in summer and autumn. The cell density of phytoplankton ranged from 8. 44 × 106 to 64. 77 × 106 cells / L,with an average value of28. 93 × 106 cells / L