长江口浮游甲壳动物空间分布特征

2010年研究了长江口南、北支浮游甲壳动物的空间分布特征。共采集到浮游甲壳动物50种,其中桡足类39种,枝角类11种。种类数南支高于北支;平均密度北支高于南支,南、北支分别为1.7 ind./L和61.8 ind./L。基于群落相似性矩阵的CLUSTER聚类和MDS分析显示,在群落相似性为40%时,长江口区域浮游甲壳动物群落可分为北支组、南支组1和南支组2共3组。3组的优势种有差异。浮游甲壳动物的平均密度变化趋势为北支组（61.8±22.11 ind./L）〉南支组1（3.07±2.06 ind./L）〉南支组2（0.72±0.45 ind./L）。盐度、潮汐和径流量是影响长江口南北支浮游甲壳动物种类组成、密度和空间分布差异的重要环境因素。

The spatial distribution characteristics of crustacean plankton in the Yangtze River estuary

The spatial distribution characteristics of crustacean plankton community in the south and north branches of the Yangtze River estuary were surveyed in 2010. A total of 50 crustacean plankton species were recorded. There were 39 species of copepods and 11 species of cladocerans. South branch species＇ number was higher than the north. The average density in the north branch was higher than that in the south. The density of crustacean in the south branch was 1. 7 ind. /L and in the north branch,it was 61. 8 ind. /L.CLUSTER and MDS analysis showed that when the community similarity was 40%,the crustacean plankton communities of the Yangtze River estuary area could be divided into three groups： the north branch group,the south branch group 1 and group 2. The main contribution species of the groups were variation. The average density of the groups＇ change trend for the north branch group（ 61. 8 ± 22. 11 ind. /L） 〉the south branch group 1（ 3. 07 ± 2. 06 ind. /L）〉 the south branch group 2（ 0. 72 ± 0. 45 ind. /L）. Salinity,tide and runoff were the important environmental factors influencing the species composition,density and spatial distribution of crustacean plankton in the south and north branch of the Yangtze River estuary.