珠江口浮游桡足类的生态研究

Study on planktonic copepods ecology in the Pearl River estuary

根据2002～2003年珠江口12个航次的调查资料,分析了浮游桡足类种类组成、优势种演替和丰度的时空变化,探讨其影响因素。以表层盐度(S)变化将调查海域划分三个区域:I区(S<25)、II区(25<S<30)和III区(S>30)。结果表明:调查海域共出现桡足类65种,II区和III区的种类多于I区;桡足类的平均丰度为118ind·m-3,三个区域之间的比较为II区(165ind·m-3)>I区(129ind·m-3)>III区(62ind·m-3),春、夏季的丰度高于冬季;优势种有明显的时间和区域上的变化。I区9个航次的研究结果表明:I区桡足类种类较少;各月份之间的平均丰度差别大,由河口内往外呈增加趋势。盐度是影响珠江口桡足类种类组成和数量变化的主要因素。

Based on the data obtained from 12 cruises from 2002 to 2003 in the Pearl River estuary, species composition, dominant species succession, abundance variations and environmental factors influence on planktonic copepods were examined. The Pearl River estuary can be divided into three regions according to its surface salinity, region Ⅰ（salinity〈25）, region Ⅱ（salinity from 25 to 30） and region Ⅲ（salinity〉30）. Results showed that total 65 species were identified. The number of zooplankton species was higher in regions Ⅱ and Ⅲ than that in region Ⅰ. The average abundance of copepods in the Pearl River estuary was 118 ind.m^-3. It was higher in regions Ⅱ （165 ind.m^-3） and Ⅰ （129 ind.m^-3） than that in region Ⅲ （62 ind.m^-3）, and it was also higher in spring and summer than that in winter. Dominant species presented obvious regional and temporal patterns. Another result from 9 cruises carried out in region I showed that copepods abundance differed monthly and generally increased from the inner to the outer of the estuary. Salinity was an important factor influencing species composition, distribution and abundance of copepods in the Pearl River estuary.