2005～2006年珠江口浮游动物群落变化研究

Study on the variation of zooplankton community in the Pearl River Estuary in 2005～2006

根据2005年4月至2006年9月珠江口4个航次19个站位的调查资料,分析了春、夏季和秋季初浮游动物的种类组成、优势种和个体数量等的时空变化,并分析了研究期间浮游动物群落的演替情况.经鉴定共发现终生浮游动物226种和阶段性浮游幼体5个类群.优势种中,除了刺尾纺锤水蚤(Acartia spinicauda)、强额拟哲水蚤(Paracalanus crassirostris)和中华异水蚤(Acartiella sinensis)等过去常见的优势种外还出现枝角类和被囊类的种类,夜光虫(Noctiluca scintillans)则是春季的第一优势种.调查海区的浮游动物可划分为河口类群、近岸类群、大洋类群和广温广盐类群.2006年浮游动物的平均个体数量高于2005年,春季的平均个体数量高于同年夏季或秋季初,空间分布则无明显规律.根据相关分析,盐度和水温是影响该海区浮游动物群落结构的重要因素.根据演替速率E值的计算结果,珠江口浮游动物群落存在明显的季节演替,但2005年至2006年间的同一季节则未出现显著的群落演替.

Based on data obtained from 19 stations ,4 cruises from April of 2005 to September of 2006 ,the temporal and spatial distributions of species composition, dominant species and abundance of zooplankton in the Pearl River Estuary in different seasons were plankton and 5 groups of plankto studied, and the community succession were analysis. Totally 226 species of holonic larva were identified. In additional to common species of Acartia spinicauda, Paracalanus crassirostris and Acartiella sinensis, species of Cladocera and Tunicata were newly dominant species. Noctiluca scintillans became the first dominant species in spring. Zooplankton in the studied area could be divided into 4 ecological groups： estuarine group, nearshore group, pelagic group, and eurythermal and euryhaline group. The abundance of zooplankton was higher in 2006 than in 2005. And it was higher in spring than in summer of the year. The ,spatial distribution of the abundance showed no significant pattern. Based on statistic analysis, salinity and temperature were the most important factors influencing the community structure. Though the succession rate （E） showed that there were notable seasonal successions, such succession was not significant in the same season of 2005 and 2006.