浙江泗礁沙滩碎波带浮游动物种类组成及其季节变化

为了探讨泗礁沙滩碎波带浮游动物的种类组成及其季节变化,2010年8月至2011年8月每月大潮期间,在泗礁沙滩碎波带设置8个站点,以浮游Ⅰ型生物网共采集到浮游动物67种,浮游幼虫10类,共计77个种类。浮游动物中甲壳动物最多,共56种,占总种数的72.73%,其中枝角类3种,桡足类43种,其他甲壳动物10种。此外,毛颚动物4种,水母类7种。优势种为小拟哲水蚤(Paracalanus parvus)、强额拟哲水蚤(Paracalanus crassirostris)、背针胸刺水蚤(Centropages dorsispinatus)等13种,其中四季皆为优势种的仅小拟哲水蚤和强额拟哲水蚤2种。泗礁沙滩碎波带浮游动物大致可分为4个生态类群,分别为河口半咸水生态类群(2种),近海暖温生态类群(2种),近海暖水生态类群(52种)和大洋广布生态类群(5种)。结果表明,泗礁沙滩碎波带浮游动物受盐度、温度、潮汐和外海水团等环境因素影响,海洋性浮游动物最多,季节变化显著,夏季优势种最多(10种),冬季最少(4种),平均密度春季最高(1 557.021个/网),冬季最低(87.875个/网)。

Composition and seasonal changes of zooplankton in the surf zone of sandy beach at Sijiao Island, Zhejiang

In order to find out the composition and seasonal changes of zooplankton in the surf zone of sandy beach in Sijiao Island,zooplankton were collected at the 8 stations by a zooplankton net (0.3 cm mouth-diameter,0.2 mm mesh-aperture) each month during the spring tide from August 2010 to August 2011. During the study period,67 species and 10 kinds of planktonic larvae were collected. They included 56 crustacean species(43 copepod species,3 cladoceran species and 10 other species),4 chaetognath species,7 medusa species. There were 13 dominant species in total,such as Paracalanus parvus,Paracalanus crassirostris and Centropages dorsispinatus. The zooplankton in the surf zone of sandy beach in Sijiao Island could be divided into four ecotypes:estuarine low salinity group(2 species),offshore warm temperate group(2 species), offshore warm water group(52 species), and eurytopic group(5 species). The results indicated that zooplankton community in surf zone of sandy beach were mostly offshore warm water group. Affected by salinity,water temperature,ocean current and other environmental factors,seasonal changes were obvious. In spring,the mean density of zooplankton was the highest,while it was the lowest in winter.