摘要
A cruise was conducted from late August to early September 2004 with the intention of obtaining an interdisciplinary understanding of the Yangtze River Estuary including the biological, chemical and physical subjects. Water sample analysis indicated that total phytoplankton species richness was 137. Of them 81 were found in Bacillariophyta and 48 in Pyrrophyta, accounting for 59.1% and 35.0% respectively. The average cell abundance of surface water samples was 8.8 ×104 cells L^-1, with the maximum, 102.9×104 cells L^-1, encountered in the area （31.75°N, 122.33°E） and the minimum, 0.2×10^4 cells L^-1, in （30.75°N, 122.17°E）. The dominant species at most stations were Skeletonema costatum and Proboscia alata f. gracillima with the dominance of 0.35 and 0.27. Vertical distribution analysis indicated that obvious stratification of cell abundance and dominant species was found in the representative stations of 5, 18 and 33. Shannon-Wiener index and evenness of phytoplankton assemblage presented negative correlation with the cell abundance, with the optimum appearing in （30.75°N, 122.67°E）. According to the PCA analysis of the environmental variables, elevated nutrients of nitrate, silicate and phosphate through river discharge were mainly responsible for the phytoplankton bloom in this area.
巡航与包括生物、化学、物理的题目获得长江河口的学科交差的理解的意愿从迟了的 8 月被进行到 2004 年 9 月上旬。水样品分析显示全部的浮游植物种类丰富是 137。他们， 81 在 Bacillariophyta 和 48 inPyrrophyta 被发现，为 59.1% 和 35.0% 的财务分别地。房间许多表水取样的一般水准是 8.8 x 10 ~ 4 房间L^(有最大值的-1),， 102.9 x 10 ~ 4 房间L^(在区域遇到的-1)( 31.75 °N ， 122.33 °E )并且最小， 0.2 x 10 ~ 4 房间L^(-1),在( 30.75 °N ， 122.17 °E )。Thedominant 种类至多驻扎是 Skeletonema 肋前缘弦音器和 Proboscia alata f。有 0.35 和 0.27 的优势的 gracillima。竖直分布分析显示房间丰富和优势种的明显的层化在 5， 18 和 33 .Shannon 牛肉熏香肠索引的代表性的车站被发现，浮游植物集合的平均与房间丰富介绍了否定关联，与出现在的最佳(30.75 ° N， 122.67 ° E ) 。为在这个区域的浮游植物花蕾主要根据通过河量的环境变量，硝酸盐的提高的营养素，硅酸盐和磷酸盐的 PCAanalysis 负责。
基金
This study was supported by the National Natural Science Foundation of China(Grant Nos.50339040,40306025)
the Chinese Academy of Sciences(No.KZCX3-SW-232).The authors are also very much indebted to the crews of the cruise.
作者简介
Corresponding author. Tel： 0086-532-82898647 E-mail： sunjun@ ms. qdio. ac. cn
