中文摘要：

分别于2009年夏季和2010年夏、秋季对黑河流域进行了2次全面调查,共选取76个采样断面进行水样采集,鉴定出浮游植物242种,隶属于8门11纲25目45科94属.其中硅藻门为优势类群,占物种总数的38.43%,绿藻门和蓝藻门次之;黑河流域优势种为尺骨针杆藻（Synedra ulna）、无常蓝纤维藻（Dactylococcopsis irregularis）和尖针杆藻（S.acus）,优势度分别为0.060、0.031和0.021,出现频度分别为43.42%、43.42%和46.05%.生物多样性指数及相关指数分析表明,黑河流域中、下游浮游植物群落结构的复杂程度和稳定性均高于上游;同时,综合生物多样性指数及相关指数以及水质理化指标表明,黑河上游水质为无污染或轻度污染,中、下游水质为轻中度污染.浮游植物丰度与环境因子的相关性分析表明,上游浮游植物丰度与水体硬度呈显著正相关;中游浮游植物丰度则与各环境因子无显著相关性;下游浮游植物丰度与水体硬度呈显著负相关,而与总氮×总磷呈显著正相关;总溶解性固体、pH值和水体硬度与全流域浮游植物丰度呈显著正相关.黑河流域浮游植物的空间分布具有与河水水文分带相对应的垂直地带性和水平地带性分异特征.

英文摘要：

Water samplings were collected at 76 sites across Heihe River basin during the comprehensive investigation in the summer of 2009 and summer and fall of 2010.242 species,which belong to 8 divisions,11 classes,25 orders,45 families and 94 genera,were identified from these water samplings.Bacillariophyta which makes up of 38.43% of the total number of the species is the dominant group,followed by Chlorophyta and Cyanophyta.Synedra ulna,Dactylococcopsis irregularis and S.acus are dominant species,whose ecological dominances are 0.060,0.031 and 0.021.And frequencies of their occurrence are 43.42%,43.42% and 46.05%,respectively.The analysis of biodiversity indicates that the complex and stability of phytoplankton community in middle and downstreams are both higher than those of upstream.The water quality of upstream is of no-pollution or slightly polluted,but slightly or moderately polluted in the middle and downstream.The correlation analysis between basin-wide total phytoplankton abundance and environment factors of water shows that the phytoplankton abundance is positively correlated with water hardness in the upstream while the midstream phytoplankton abundance is not significantly related with any factors.In the downstream,the phytoplankton abundance is negatively correlated with water hardness but positively correlated with nutrient index of the total nitrogen multiply by the total phosphorus（TN × TP）.In the whole basin,phytoplankton abundance is positively correlated with total dissolved solids,pH and water hardness.The spatial distribution of phytoplankton in Heihe River basin shows obvious vertical zonality and horizontal zonality corresponding to differentiation characteristics of river hydrological zonation.These results showed the spatial correlationship between phytoplankton communities and their natural environment backgrounds.We hope this research could be favor to make policies to improve the management and sustainable utilization of the aquatic biological resources,to protect the water ecological