2018-2019年舟山近海浮游动物群落结构春季年际变化及其与水团的关系

Spring interannual changes of zooplankton community structure and the influencing factors of water masses in the Zhoushan nearshore waters during 2018-2019

根据2018-2019年春季两个航次在舟山近海进行的浮游生物调查结果,对舟山近海的浮游动物群落结构(类群组成、优势种数量)年际变化进行了研究,利用典范对应分析(Canonical Correspondence Analysis,CCA)研究了两年春季浮游动物类群组成差异、优势种变化的原因,初步探讨了春季浮游动物群落结构动态变化的机制。结果表明:根据表层温度(Sea Surface Temperature,SST)、表层盐度(Sea Surface Salinity,SSS)的聚类分析,将该区域分为3个水团:杭州湾内水团(Ⅰ区)、舟山本岛上升流水团Ⅱ区)、舟山近海水团(Ⅲ区)。不同水团对浮游动物类群组成影响显著,引起2018年和2019年春季3个水团区差异的主要贡献种(贡献率>10%)均为中华哲水蚤,同一水团两年间年际差异的贡献种如下:Ⅰ区为捷氏歪水蚤(56.91%)和真刺唇角水蚤(12.34%);Ⅱ区为中华哲水蚤(72.64%)、五角水母(13.35%);Ⅲ区为中华哲水蚤(41.93%)、夜光虫(22.94%)。CCA分析表明,第1 CCA轴(CCA1)和第2CCA轴(CCA2)共解释了两年春季浮游动物优势种累计方差的46.14%和物种-环境累计方差的97.82%。CCA1主要反映了空间(近海水团和湾内水团)的差异。CCA2主要反映了2018年和2019年站位的年际差异。盐度是影响春季浮游动物群落结构空间差异的主要因素,而温度、叶绿素a浓度是春季浮游动物群落结构年际差异的主要因素。

According to two years(2018-2019) spring plankton surveys in the Zhoushan coastal waters, the zooplankton community structure(species composition, abundance of dominant species) were investigated, the canonical correspondence analysis(CCA) was used to study spring interanuual difference of zooplankton community and causes of their dynamics, the mechanism of community dynamics were discussed according to our results.The results show that the study region is divided into three groups according to cluster analysis of sea surface temperature(SST) and sea surface salinity(SSS): Hangzhou Bay water masses(Area Ⅰ), upwelling water masses in Zhoushan Island(Area Ⅱ), and water masses in Zhoushan offshore area(Area Ⅲ). Water mass groups have significant influence on the composition of zooplankton community. The main species contributing to the difference between the three water masses in spring 2018 and spring 2019(contribution rate >10%) are Calanus sinicus. The contribution species of the same water mass in two years were: Tortanus derjugini(56.91%) and Labidocera euchaeta(12.34%) in Area Ⅰ,Calanus sinicus(72.64%) and Muggiaea atlantica(13.35%) in Area Ⅱ, Calanus sinicus(41.93%) and Noctiluca scintillans(22.94%) in Area Ⅲ. CCA shows that the first CCA axis(CCA1) and the second CCA axis(CCA2) explained 46.14% of the accumulated variance of the dominant species of zooplankton and 97.82% of the species-environment accumulated variance in spring 2018 and spring 2019. CCA1 mainly reflects the spatial difference between the offshore water mass and the Hangzhou Bay water mass. CCA2 mainly reflects the interannual difference between the stations in 2018 and 2019. Salinity is the main factor influencing the spatial difference of zooplankton community structure in spring, while temperature and chlorophyll a concentration are the main factors controlling the interannual difference of zooplankton community structure in spring.