渤海中部浮游动物的生态特征

本研究针对2013年5月(春季)、8月(夏季)、11月(秋季)和12月(冬季)在渤海中部海域以浅水Ⅰ型浮游生物网采集的浮游动物样品，分析了浮游动物的种类组成、丰度分布和多样性；通过结合现场环境参数，探讨了环境因子与浮游动物之间的关系。结果显示，4个季节共鉴定浮游动物74种(含浮游幼虫21类)，桡足类为绝对优势的类群，在浮游动物的物种丰富度中占25.7%。渤海中部海域全年均出现的浮游动物优势种类共2个，分别为中华哲水蚤(Calanus sinicus)和强壮箭虫(Sagitta crassa)。春季共鉴定浮游动物29种(含浮游幼虫6类)，浮游动物平均丰度为782.0 ind/m3，平均湿重生物量为157.1 mg/m3，香农-威纳指数(H’)和物种丰富度指数(D)分别为2.36和1.02；夏季共鉴定浮游动物45种(含浮游幼虫18类)，浮游动物平均丰度为199.6 ind/m3，平均湿重生物量为135.8 mg/m3，H’和D分别为1.75和1.78；秋季共鉴定浮游动物42种(含浮游幼虫14类)，浮游动物平均丰度为42.1 ind/m3，平均湿重生物量为122.5 mg/m3，H’和D分别为1.83和2.08；冬季共鉴定浮游动物33种(含浮游幼虫12类)，浮游动物平均丰度为72.1 ind/m3，平均湿重生物量为151.1 mg/m3， H’和D分别为1.63和1.53。浮游动物丰度与环境因子间的相关性分析表明，春季影响渤海中部海域浮游动物分布的主要环境因子组合为表盐、底溶解氧和水深；夏季影响渤海中部海域浮游动物分布的主要环境因子组合为底温、底盐和叶绿素；秋季影响渤海中部海域浮游动物分布的主要环境因子组合为表温、表pH和底pH；冬季影响渤海中部海域浮游动物分布的主要环境因子组合为底pH和叶绿素。与同期历史数据相比，浮游动物的种类数、丰度和生物量均有所下降。

The Ecological Characteristics of Zooplankton in the Central Bohai Sea

Studies on the species, abundance and distribution of zooplankton have been extensive and mainly focused on either the entire or certain small parts of the Bohai Sea. In this study, we analyzed the composition, abundance, dominant species, and biodiversity of zooplankton based on samples collected in the central Bohai Sea in 2013. The distribution and its influencing factors were explored with multivariate analysis according to the sampling date and environmental parameters. A total of 74 zooplankton species/taxa (including 21 pelagic larvae) were identified in four surveys. Copepods were the most abundant species. The numbers of pelagic copepod and medusa species accounted for 25.7% and 24.3% of the total species respectively. The composition of the dominant species was consistent with previous reports. TheCalanus sinicus and Sagitta crassa were the dominant species. The abundance of C. sinicus andS. crassa explained 19.5%–50.3% and 7.3%–39.6% of the total zooplankton abundance respectively. In spring, the average abundance, the average biomass, the Shannon-Wiener index (H′), and the Margalef′s index (D) were 782.0 ind/m3, 157.1 mg/m3, 2.36, and 1.02 respectively. In summer, the values of parameters above were 199.6 ind/m3, 135.8 mg/m3, 1.75, and 1.78. In autumn, they were 42.1 ind/m3, 122.5 mg/m3, 1.83, and 2.08 respectively. In winter, they were 72.1 ind/m3, 151.1 mg/m3, 1.63, and 1.53 respectively. The abundance and biomass fluctuated and showed distinct heterogeneity in the central part of the Bohai Sea. There was a seasonal variation in the primary environmental factors that affected the distribution of zooplankton. In spring, they were surface salinity, bottom DO, and water depth. In summer, they were bottom temperature, bottom salinity, and chlorophyll. In autumn, they were surface temperature, surface pH, and bottom pH. In winter, they were bottom pH and chlorophyll. Our research provided the fundamental information on the long-term observation of zooplankton ecology in the central part of the Bohai Sea. Compared to the data collected in 1959, 1998, and 2006, the number of species, abundance and biomass of zooplankton have decreased.