中文摘要：

衡水湖湿地对维护区域生态平衡和促进地区经济社会可持续发展具有重要作用。基于主成分分析法和综合营养指数法对衡水湖湿地水质进行了研究，分析了沉积硅藻组合与水质的关系。主成分分析结果表明，衡水湖四季水质变化较大，冬季水质最好，为Ⅰ类水，夏秋较差，已超标，引起水质恶化和影响藻类生长的主要环境因子是TP、DO和TN；综合营养指数法分析结果确定衡水湖为中-富营养型湖泊。沉积硅藻组合显示，衡水湖是以附生种、浮游种和底栖兼浮游种多生态型硅藻组合为特点，且耐营养度较低指示污染水体的Ach-nanthes minutissima（20.90%）和Cymbella microcephala（18.83%）为优势种，可较好地反映衡水湖富营养状况，衡水湖湿地水质与沉积硅藻组合的关系密切。

英文摘要：

Hengshui Lake plays an important role in maintaining the regional ecology balance and promoting the sustainable de-velopment of regional economy and society. The water quality and the relationship between sedimentary diatoms assemblage and water quality are studied on the basis of the component analysis and comprehensive nutrition index method. The results of princi-pal component analysis indicate that the water quality of Hengshui Lake varies with seasons, which is the best in winter （ class I） , while relative worse in summer and exceeding the standard. TP, TN and DO are the main environmental factors that cause the deterioration of water quality and affect the growth of diatom. By using the comprehensive index method analysis, it is conclu-ded that Hengshui Lake is in mesotrophication or eutrophication. The diatoms assemblage indicates that the sedimentary diatom assemblage of Hengshui Lake is characterized by multivariate ecotypes, such as epidiatoms, plankton-species and benthic spe-cies. Moreover, the species of Achnanthes minutissima （20. 90%） and Cymbella microcephala （18. 83%） with low eutrophica-tion-resistent are the dominant species, so it can reflect the status of mesotrophication or eutrophication and the relationship be-tween water quality and sedimentary diatoms assemblage in Hengshui Lake.