象山港浮游动物的分布特征及其中长期变化

Distribution of zooplankton in the Xiangshan Bay and its changes during longer period

为更好地了解象山港海湾浮游动物群落的现状,保护海洋生态环境,分别于2015年1、4、7、10月在象山港海域进行了25个站位的4个航次生态综合调查,结果表明:4个航次共鉴定出98种浮游动物和20类浮游幼体,优势种共21种,无4季共有优势种。浮游动物群落具有明显的季节变化,平均丰度(ind/m3):夏季(186.2±96.4)>春季(152.6±112.1)>秋季(56.8±30.2)>冬季(15.4±22.2);平均生物量(mg/m3):春季(90±75)>夏季(52±24)>秋季(26±19)>冬季(14±11);平均多样性指数:秋季(2.305±0.370)>夏季(1.908±0.449)>春季(1.622±0.578)>冬季(1.348±0.474)。聚类和多维尺度分析表明,春、夏和秋季3个季节浮游动物群落结构具有明显区域性差异,港口部和口外部海域的群落聚类明显,与其他群落之间相似度最低。分析象山港近35年的浮游动物历史数据表明,浮游动物丰度和生物量的下降可能与陆源排污、水产养殖污染和滨海电厂建设等人类活动有关。

To better understand the situation of zooplankton community and protect marine ecological environment,we conducted a winter(January),spring(April),summer(July)and autumn(November)survey in the Xiangshan Bay.In the four seasons,we totally documented 98 species and 20 larvae of zooplankton,with 21 dominant species.However,there was no one specie which kept dominant for a whole year.The abundance,biomass,Shannon-Wiener diversity index and Pielou's evenness index of zooplankton all had obvious seasonal variation.Besides,according to cluster and Multidimensional-Scaling(MDS)Analysis,there was a great discrepancy among most communities of zooplankton at different areas of the Xiangshan Bay in spring,summer and autumn,specially between communities of embayment mouth and the others.By analyzing the zooplankton data in the past 35 years in the Xiangshan Bay,we found that the abundance and biomass both presented a decreasing trend,which may be related to the various human marine exploitation in the bay.