大陈岛海域浮游动物群落季节变化及其影响因素

为探究大陈岛海域浮游动物群落的季节变化，于2020年9月（夏季）、11月（秋季）和2021年1月（冬季）、4月（春季）分别对大陈岛海域的浮游动物及环境因子进行了4个航次的调查。结果共鉴定浮游动物90种，包括浮游幼体15类，其中夏季种类数最多（68种），冬季最少（20种），常见的优势种有：百陶箭虫（Sagitta bedoti）、微刺哲水蚤（Canthocalanus pauper）、中华哲水蚤（Calanus sinicus）等12种（Y>0.02）。浮游动物的年平均丰度和生物量分别为（153.40±214.73）个/m³、（411.93±561.76） mg/m³，二者存在明显的季节变化，平均丰度为春季（380.17±296.14）个/m³>夏季（135.30±112.59）个/m³>秋季（67.88±90.52）个/m³>冬季（25.30±19.11）个/m³；平均生物量为夏季（895.01±802.54） mg/m³>春季（623.39±358.73） mg/m³>秋季（91.08±82.36） mg/m³>冬季（45.96±84.95） mg/m³。多样性指数（H''）和均匀度指数（J''）的年平均值分别为1.71±0.96和0.53±0.20，均表现出夏秋季较高、冬春季较低的特征。聚类分析结果表明调查海域的浮游动物可划分为夏季类群、秋季类群、冬季类群和春季类群4组类群。Pearson相关性分析和冗余分析（RDA）结果表明，海水温度、盐度、叶绿素a浓度是影响大陈岛海域浮游动物群落特征的重要环境因素。此外，夏季大陈岛海域水母类浮游动物暴发的现象值得关注。研究结果将为大陈岛海域的生物多样性保护及渔业资源可持续开发利用提供可参考的数据资料。

Seasonal variation and environmental factors of zooplankton communities in sea areas around Dachen Island

We conducted four investigations on the seasonal variation of zooplankton communities in sea areas around Dachen Island in September (summer) and November (autumn) 2020, January (winter) and April (spring) 2021. A total of 90 zooplankton species (including 15 types of pelagic larvae) were identified, with the maximum of species richness in summer (68 species) and the minimum of species richness in winter (20 species). There were 12 dominant species (Y>0.02) including Sagitta bedoti, Muggiaea atlantica, Furcilia larva, Sagitta enflata, Calyptopis larva, Euchaeta concinna, Diphyes chamissonis, Acartia pacifica, Canthocalanus pauper, Paracalanus aculeatus, Pseudeuphausia sinica, and Calanus sinicus. The seasonal variations were revealed in the abundances and biomass of zooplankton communities, whilst the annual average abundance and biomass were (153.40±214.73) ind/m³ and (411.93±561.76) mg/m³, respectively. The average abundance from highest to lowest was (380.17±296.14) ind/m³ in spring, (135.30±112.59) ind/m³ in summer, (67.88±90.52) ind/m³ in autumn, (25.30±19.11) ind/m³ in winter. The average biomass from highest to lowest was (895.01±802.54) mg/m³ in summer, (623.39±358.73) mg/m³ in spring, (91.08±82.36) mg/m³ in autumn, (45.96±84.95) mg/m³ in winter. The annual average Shannon-Wiener diversity index (H'') and Pielou''s evenness index (J'') were 1.71±0.96 and 0.53±0.20, respectively, which were higher in summer and autumn and lower in winter and spring. Hierarchical cluster analysis revealed that the zooplankton communities could be divided into four groups, including summer group, autumn group, winter group, and spring group. Pearson correlation and RDA analysis showed that water temperature, salinity, and chlorophyll a were main factors related to the distribution and variation of zooplankton communities. In addition, it was noticeable that jellyfish has occurred increasingly and abundantly in summer in sea areas around Dachen Island. Our result will provide useful data for the conservation of biodiversity and sustainable utilization of fishery resources in the marine ecosystem around Dachen Island.