【摘要】 <正> 浮游动物群落的结构只有相对的稳定性。随着季节的转换,海洋环境条件的变化,不仅种类组成更迭频繁,羣落中各种之间的数量关系亦经常不断地有所变动。因此,浮游动物群落的界限是比较难以确定的。同时,浮游动物群落的生活小区的分界,也常常是不十分明确的。一般说来,在理化性质比较均一的水系或水团中,浮游动物韦落的结构,相对更多还原

【Abstract】 An analysis of data obtained from several years of plankton investigation carried out in the Yellow Sea and in the East China Sea shows that the zooplankton of the Yellow Sea is characterized by warm temperate elements, and that of the East China Sea, by elements of different ecological nature; its northern part is inhabited chiefly by warm temperate species with a few tropical species, its southern and eastern part, by tropical species and its western part close to shore, by a mixture of warm temperate and tropical species. The zooplankton of these two seas may be grouped into seven communities, each with its characteristic and dominant species and each occupying a definite water body. There is a seasonal succession of species.The boundaries of the biotopes of the different planktonic communities shift with changes in hydrographic conditions, in particular, with changes in the movement of water masses and currents in various seasons. In the late summer and the early fall, when runoffs from various rivers pour into the Gulf of Pohai, Community Ⅰ occupies the entire gulf, while the biotopes of Community Ⅱ and Ⅲ are extended to the central area of the northern Yellow Sea, which is also inhabited by Community Ⅳ. From the late fall to the spring of the following year, when runoffs from rivers are low, the biotope of Community Ⅳ is extended to the center of the Gulf of Pohai and to the coast of southern Liaoning and Shantung Provinces, while the biotope of Community Ⅰ is pushed back shorewards. The biotope of Community Ⅴ which was previously restricted to the coastal area of northern Chiangsu expands southward. In summer, when there are high runoffs from the Yangtze and Tsientang Rivers, and when the influence of branches of the warm current off the Chekiang coast is rather strong, warm and highly saline water intrudes from the underlayers, while coastal, low saline water flows offshore, resulting in overlapping of two different water bodies and hence of their respective communities--thatis, Community Ⅵ and Community Ⅶ. In autumn, with a decrease in the amount of runoffs from the Yangtze River, the biotope of Community Ⅵ is restricted to the near-shore regions, while the biotope of Community Ⅶ expands to the coastal areas of Chekiang. In winter and early spring, when coastal currents prevail and the southward flow of the cold water mass of the Yellow Sea is rather intensified, the biotope of Community Ⅵ on the one hand contracts close to the mouth of the Yangtze River, and on the other hand expands to the offshore waters of the Chusan Archipelago. The southern boundary of the biotope of Community Ⅳ is also expanded southward. At the same time there is intrusion of some tropical species into Community Ⅳ. This is apparently brought about by the prevailing influence of the Yellow Sea Warm Current. In general, the pattern of the seasonal variation in structure and in shift of boundaries of the biotopes of the zooplankton communities in the Yellow Sea and in the western East China Sea in winter and spring is more or less similar, that in summer and autumn is also more or less similar, but the difference in pattern between the first two seasons and the last two seasons is rather marked.更多还原