象山港冬季浮游动物的分布

对2002年12月象山港海区的浮游动物种类组成和数量分布特征及其与环境的关系进行了研究。结果表明,象山港海区出现浮游动物44种,可以划分为4个生态类群,其中近岸低盐性类群的种类较多,其优势种有真刺唇角水蚤Labidoceraeuchaeta、驼背隆哲水蚤Acro-calanusgibber、中华哲水蚤Calanussinicus、中华假磷虾Pseudeuphausiasinica和拿卡箭虫Sagittanagae等,半咸水河口类群、暖水性外海类群和广盐暖水性类群的种数均较少。浮游动物生物量的分布趋势与丰度的一致。湾顶部水域浮游动物的生物量和丰度都出现最高值,从湾顶部往湾口方向,浮游动物的生物量和丰度均呈逐渐降低的趋势。象山港海区周日连续站观测的结果显示,夜间半日潮时浮游动物的生物量和丰度均高于白昼半日潮时,低平潮时浮游动物的生物量与丰度均出现了最高值。

Distribution of zooplankton in the Xiangshangang Bay in winter

Based on the sample collected from the environmental survey in the Xiangshangang Bay during the period of December 2002, the species composition of zooplankton, distribution characteristics of biomass and abundance of zooplankton were analyzed, and relations between the community structure and environment were described in this paper. The results showed that the zooplankton in the surveyed area could be divided into 4 ecotypes, which were named (1) coastal low saline species, (2) estuary brackish water species, (3) offshore warm water species and (4) eurytopic species. There existed 44 species of zooplankton which were identified in the Xiangshangang Bay in December 2002. The horizontal distribution trend of biomass and abundance of the zooplankton were similar. The highest biomass and abundance of zooplankton appeared in the upper bay, from the upper bay towards to the lower bay, they gradually decreased. The coastal low saline ecotype was the dominant groups in the study area, and the dominant species were Labidocera euchaeta, Acrocalanus gibber, Calanus sinicus, Pseudeuphausia sinica and Sagitta nagae etc.Results of diurnal serial investigation indicated that biomass and abundance of zooplankton in nightly tide were higher than that of daily tide. The highest biomass and abundance appeared at the lowest tide.