中文摘要：

三沙湾口小腹大,为我国典型亚热带海湾,受湾内外不同水团影响,其浮游动物生态类群不同季节变化显著,对研究浮游动物群落适盐性受湾外水团和湾顶大陆径流影响具有重要意义.本文通过研究三沙湾海域2010年6月、8月、10月和2011年4月、5月共5个航次浮游动物生态类群种数和丰度的时空分布,重点分析了其适盐性分布特征,并初步探讨了湾内外不同水团交替变化对浮游动物生态类群结构的影响.共鉴定浮游动物71种,其中近海种36种,外海种34种,热带大洋种1种;4月和5月,近海种种数比例分别为94.12%和78.95%,近海种丰度比例分别为98.46%和97.57%;6月、8月和10月,近海种种数比例分别为51.11%、42.86%和42.42%,近海种丰度比例分别为82.88%、40.07%和53.24%.研究表明,4月和5月,因受湾外浙闽沿岸流和湾内大陆径流影响,浮游动物以近海种为主,空间分布差异较小;6月、8月和10月,主要受湾外台湾暖流影响,大量外海种在湾内水域出现,并且空间差异显著,呈现出由湾内至湾外浮游动物外海种种数和丰度比例逐渐增大的趋势.

英文摘要：

For a comprehensive understanding of the interactive relationships of zooplankton ecogroups and their response to the changing water masses, the species composition and horizontal distribution of zooplankton in the Sansha Bay was analyzed to study the effect of water masses on the salinity adaptation of zooplankton. Distribution of zooplankton were investigated from samples collected from 10 stations during 5 oceanographic cruises in April, May, June, August and October in the Sansha Bay. All together 71 species were identified, including 36 nearshore species and 34 offshore species. The result showed significant differences in structures of ecogroups among months. In April and May, the nearshore species accounted for more than 97% of the total zooplankton abundances for all stations. The ambient water was influenced by the continental fresh runoff and the Zhemin Coastal Current, both with low salinity. From June to October, the abundance percentage of nearshore species fluctuated between 40.07% and 82.88%. There were significant differences between the two characteristic zooplankton communities in the northwestern and southeastern parts of the Bay, probably due to the effect of the Taiwan Warm Current. The northwestern part was characterized by high proportions of nearshore species in both number and abundance. The outer Bay of the southeastern part was characterized by relatively high proportions of offshore species in number and abundance. Our research revealed that the salinity adaptation and the temporal and spatial distribution of zooplankton are closely related to the currents changing with season.