中文摘要：

2005年1～12月，对珠江广州河段浮游植物和相关理化因子进行了周年调查．结果表明：广州河段TN和TP含量丰富。中大码头TN和TP年平均质量浓度分别为10．92mg·L^-1和0．41mg·L^-1，黄埔港为9．59mg·L^-1和0．29mg·L^-1；Chl．a质量浓度较高，两站点的年平均质量浓度分别为121．83μg·L^-1和72．33μg·L^-1，最大值达400μg·L^-1和190μg·L^-1．调查期间，发现浮游植物127种，主要优势种为颗粒直链藻（Melosira granulata）、假鱼腥藻（Pseudanabaena sp．），两优势种有明显的季节演替现象，4月份以前主要以假鱼腥藻占优势，之后以颗粒直链藻占绝对优势．丰水期，浮游植物密度较低，枯水期，浮游植物密度较高．总体上，中大码头浮游植物数量高于黄埔港；最高峰都出现在秋季，中大码头达2．88×10^7／L，黄埔港达1．37×10^7／L．研究发现径流量和TP质量浓度对浮游植物密度有重要影响，此外，浮游植物种群变动还受温度、盐度等因素的影响．

英文摘要：

The water quality and ecological characteristics of phytoplankton in the Guangzhou segment of the River Pearl, China, were investigated from January to December, 2005. Samples were taken at two fixed sites（ Zhongda Port and Huangpu Harbor）. The results showed that the trophic level of the two sites were very high, the annual average concentrations of TN were 10. 92 mg · L^-1 and 9.59 mg · L^-1 , TP were 0. 41 mg · L^-1 and 0. 29 mg· L^-1 , in zhongda Port and Huangpu Harbor respectively. Annual average concentrations of Chl. a were 121.83 μg · L^-1 and 72. 33 μg · L^-1 in Zhongda Port and Huangpu Harbor, respectively. 127 species of phytoplankton were recorded during the survey period. The dominant species were Melosira granulate, Pseudanabaena sp. , and they changed with an obvious seasonal succession. Results indicated that river discharge and TP had significant effects on the densities fluctuation of phytoplankton. The high densities were recorded in the low water season （ dry period） and the low densities were in the rainy season （flood period）. In addition, salinity and temperature could influence phytoplankton community structure and seasonal succession.