长江口3个不同生态系的浮游植物群落

Phytoplankton Communities in Three Distinct Ecotypes of the Changjiang Estuary

初步研究表明 ,长江口及邻近海域存在 3个不同的生态系 ,与以盐度划分的水团 (长江河口水、长江冲淡水、外海水 )基本一致 ,每个生态系包含 1个浮游植物群落。 1997～ 2 0 0 0年的 7个航次调查中共鉴定出浮游植物 393种 ,其中大部分为硅藻。长江口的浮游植物基本可归为 5个类群 :淡水类群、河口半咸水类群、近岸低盐性类群、外海高盐类群、海洋广布性类群。它们自西向东在 3个生态系中有明显的分布格局 ,并且随着长江径流量的变化而摆动和变化。根据栖息水域的盐度浮游植物可分为 3个群落 :河口群落、冲淡水低盐群落、外海高盐群落。

In the Changjiang Estuary and nearby sea area, 393 phytoplankton species, most of which were diatoms, were identified at the end of the 20 th century covering three different ecosystems which were almost in accord with the distribution of salinity. The phytoplankton can be divided into five components: a fresh water component inside the river mouth, a true estuarine component, a coastal component, a euryhaline marine component, and a high salinity component. Three distinct communities difined on the basis of salinity (the estuarine community, the Changjiang dilute community and the high salinity community) dominate three ecotypes from west to east and fluctuate with the Changjiang dilute water range in different seasons.