中文摘要：

根据2006年8月在长江口及其邻近水域（30°30’N～32°30’N，121°E～123°E）39个观测站采集的浮游植物水样，研究了该水域浮游植物群集特征。调查区浮游植物以硅藻和甲藻为主，此外还有少量的金藻、蓝藻和绿藻。浮游植物主要优势物种为脆指管藻（Dactyliosolen fragilissima）和中肋骨条藻（Skeletonema costatum）。浮游植物细胞丰度介于0．27～4830．09cells·mL^-1，平均为290．92cells·mL^-1，高值出现在调查区122°30’E～123°E水域，近岸细胞丰度较低。浮游植物细胞丰度的垂直分布特征是随水深增加先增大后减小，最大值出现在10m层。调查区两个断面细胞丰度由沿岸至冲淡水域呈增加趋势，但在调查区靠近外海一侧出现细胞丰度最低值。

英文摘要：

Water samples for phytoplankton were investigated from the grid survey around the Yangtze River Estuary and its adjacent water on August 2006. Phytoplankton assemblages and cell abundance were reported in this paper. The main phytoplankton group was diatom and the second was dinoflagellate. There were also a few species belonging to Chrysophyceae, Chlorophyceae, and Cyanophyceae. The dominant species were DactyliosoIen fragilissima, and Skeletonema costatum. The cell abundance of phytoplankton ranged from 0.27 to 4830.09 cells ·mL^-1 and the average was 290.92 cells·mL^-1. The larger cell abundance existed in the 122°30＇E-123° area, the lower cell abundance existed in onshore. Meanwhile, phytoplankton cell abundance firstly increased and then rapidly reduced, the maximum cell abundance existed in subsurface water layer. According to the section distribution, in survey area cell abundance increased from seacoast to offshore, but the lowest cell abundance existed beside the wideside of survey area.