根据2006年2月～11月在长江口及其邻近水域的采样调查,对调查水域网采浮游植物群落结构特征进行了研究.共鉴定出浮游植物5门72属177种(包括未定名种),浮游植物以硅藻为主,但甲藻在群落中的比重也很明显,此外还有少量的绿藻、蓝藻和金藻.浮游植物优势物种以可形成链状群体的物种为主,中肋骨条藻(Skeletonema costatum)在长江口水域全年都具有较高的优势度,另外还有季节性的优势种,春季的夜光藻(Noctiluca scientillans)和具齿原甲藻(Prorocentrum dentatum),夏季的细长翼鼻状藻(Proboscia alata f. gracillima),秋、冬季的琼氏圆筛藻(Coscinodiscus jonesianus)和星脐圆筛藻(Coscinodiscus asteromphalus).浮游植物物种多为温带近岸种,少数为暖水种或大洋高盐种.长江口水域网采浮游植物的细胞平均丰度在夏季最高,为2027.41×104 cells m-3,其次为春季,秋季最低,为22.15×104 cells m-3.冬季的细胞丰度在各站之间变化幅度是最小的.浮游植物物种组成、细胞丰度及多样性指数在区域上和时间上都表现出明显的差异.调查所获4季度月网采浮游植物的丰度资料与历史资料基本吻合,季节变化也基本一致,但也有个别季度差别较大,长江径流量的年际变动可能是造成这种差别主要原因之一.%A multidisciplinary study on netz-phytoplankton community was carried out in Changjiang (Yangtze) River Estuary and adjacent waters February to November, 2006. In total, 5 phyla, including 72 genera and 177 species were identified (including uncertain species), of which chain-shaped ones were dominant, in which diatoms dominated, and dinoflagellates went the second place. Species of Chlorophyta, Cyanophyta and Chrysophyta, were also found. Skeletonema costatum prevailed cross-season in the whole investigation period, while some others, seasonally, such as Noctiluca scientillans and Prorocentrum dentatum in spring, Proboscia alata f. gracillima in summer, Coscinodiscus jonesianus in autumn, and Coscinodiscus asteromphalus in winter. In the study areas, temperate coastal species were the major ecotype, while warm water species and oceanic species were occasional. Cell abundance decreased in turn from summer, spring, winter, to autumn, in average values of summer and autumn at 2027.41×104 and 22.15×104 cells m-3, respectively. The species composition, abundance and diversity varied clearly in spatial and temporal dimensions. The variation patterns of cell abundance are largely consistent with those shown by historical data, except for certain cases. Change in annual runoff of the river is believed responsible for the variations.
展开▼
