珠江口枯水期和丰水期中小型浮游动物群落动态

Community dynamics of meso-and micro-zooplankton in the Pearl River Estuary in dry and wet seasons

根据珠江口枯水期(2013年11月)和丰水期(2014年8月) 24个站位调查资料,对中小型浮游动物种类组成、丰度分布、群落结构及其主要影响因子进行了研究.结果表明,枯水期和丰水期分别鉴定浮游动物成体91种和70种,以桡足类最为丰富.浮游动物种类从河口上游向外围逐渐增加.浮游动物丰度时空分布差异显著,丰水期平均值高达11 619. 78 ind/m^3,显著高于枯水期的1 707. 13 ind/m^3.桡足类在珠江口中小型浮游动物中占绝对优势,枯水期和丰水期分别占总丰度的80. 3%和93. 0%,对浮游动物的丰度分布起关键作用.强额孔雀哲水蚤(Parvocalanus crassirostris)、中华异水蚤(Acartiella sinensis)和刺尾纺锤水蚤(Acartia spinicauda)在两个水期均为主要优势种,小拟哲水蚤(Paracalanus parvus)和厦门矮隆哲水蚤(Bestiolina amoyensis)则分别在枯水期和丰水期具有较高的优势度.聚类分析的结果显示,枯水期和丰水期该水域浮游动物均可划分为3个群落.相关性分析表明,珠江口中小型浮游动物群落结构受多个环境因子的影响,但盐度是其中最为关键的非生物因子.

Zooplankton samples were collected from 24 stations in 2 investigations in the Pearl River Estuary in November 2013 (dry season) and August 2014 (wet season).The meso- and micro-zooplankton composition,abundance,distribution and community structures and the environmental influence were studied.The results showed that there were 91 and 70 zooplankton species,mainly copepods,identified in the dry and wet seasons,respectively.The number of zooplankton species increased gradually from the upper reach of the estuary to the outer waters.The abundance of zooplankton was found varying obviously with time and geographic locations.The average zooplankton abundance in the wet season (11 619.78 ind/m^3) was much higher than in the dry season (1 707.13 ind/m^3).Copepod was the predominant species and its abundance accounted for 80.3% and 93.0% of the total in the dry and wet seasons.They plays a key role in controlling the abundance distribution of zooplankton.Three species of copepods of Parvocalanus crassirostris,Acartiella sinensis and Acartia spinicauda were dominating in 2 investigations.The abundance of other two species,Paracalanus parvus and Bestiolina amoyensis varied distinctly with seasons.Hierarchical cluster analysis classified 3 zooplankton groups from 2 seasons.Correlation analysis indicated that the dynamics of zooplankton community was determined by several factors in which the salinity was the most important abiotic factor.