珠江口枯水期和丰水期中小型桡足类种类组成、丰度分布及其与环境因子的关系

摘要

中小型桡足类是河口区浮游动物的重要组成部分.根据珠江口枯水期(2013年11月)和丰水期(2014年8月)24个站位的调查资料,对中小型桡足类种类组成、丰度分布和优势种等特征进行了研究.枯水期和丰水期中小型桡足类分别出现60和40种,以河口和近岸类群为主.根据表层盐度变化将珠江口分为Ⅰ、Ⅱ、Ⅲ区,桡足类种类分布具有显著的河口特征,枯水期和丰水期盐度均为Ⅲ区＞Ⅱ区＞Ⅰ区.相关性分析结果显示,桡足类种类数与盐度呈极显著正相关.桡足类丰度时空分布差异显著,丰水期(10 809.05 ind/m3)显著高于枯水期(1 371.20 ind/m3),且在2个水期均以Ⅰ区丰度最高.强额孔雀哲水蚤(Parvocalanus crassirostris)和中华异水蚤(Acartiella sinensis)在2个水期均为主要优势种,其空间分布亦与盐度密切相关.研究结果表明盐度是影响珠江口中小型桡足类种群结构的关键非生物环境因子.%Meso-and micro-copepods are the major species of estuarine zooplankton.Based on investigations of 24 stations in the Pearl River Estuary in November 2013 (dry season) and August 2014 (wet season),the species composition,abundance distribution and dominant species of meso-and micro-copepods were studied.Results showed that there were 60 and 40 copepod species identified in the dry and wet season,respectively,mostly belonging to the estuarine and neritic groups.In our study,the Pearl River Estuary was divided into three regions according to its surface salinity.The Distributions of species number in both dry and wet seasons were Region Ⅲ ＞Region Ⅱ ＞Region Ⅰ,displaying a remarkable characteristic estuarine distribution.The species number of copepod was significantly correlated with salinity.The abundance of copepod was found varying with time and geographic locations.The average copepod abundance in the wet season (10 809.05 ind/m3) was much higher than in the dry season (1 371.20 ind/m3),and in both seasons Region Ⅰ had the highest copepod abundance.Moreover,the two copepods of Parvocalanus crassirostris and Acartiella sinensis were found dominant in both seasons,and their distributions were significantly correlated with salinity.In conclusion,salinity was the key abiotic factor influencing copepod population structure in the Pearl River Estuary.