舟山群岛邻近海域浮游动物生态研究——Ⅰ．种类组成与数量分布

根据1990年春季(4~5月)和秋季(10~11月)在舟山群岛附近海域所采集的浮游动物样本及相关环境资料,春季,共鉴定出浮游动物104种,秋季,共鉴定出浮游动物106种;分析了浮游动物生物量和丰度的平面分布、季节变动及其与环境因子的关系。结果表明:春、秋季调查海区的浮游动物种类数基本相同,但种类组成却发生了明显的变化,两个季节浮游动物的共同种只有54种,约50%的种类发生更替,其中桡足类和水螅水母类的种类更替较明显;浮游动物生物量和丰度春季高于秋季;浮游动物种类组成、生物量和丰度的变化与水文环境变化密切相关。     

北太平洋亚热带环流区与西太平洋暖池区浮游动物群落垂直分布的差异及其对碳通量的意义

The mesozooplankton in both epipelagic and mesopelagic zones is essentially important for the study of ecosystem and biological carbon pump. Previous studies showed that the diel vertical migration(DVM) pattern of mesozooplankton varied among ecosystems. However, that pattern was largely unknown in the Western Pacific Warm Pool(WPWP). The vertical distribution, DVM and community structure of mesozooplankton from the surface to 1 000 m were compared at Stas JL7K(WPWP) and MA(North Pacific Subtropical Gyre, NPSG). Two sites showed similarly low biomass in both epipelagic and mesopelagic zones, which were in accordance with oligotrophic conditions of these two ecosystems. Stronger DVM(night/day ratio) was found at JL7K(1.31) than that at MA(1.09) on surface 0–100 m, and an obvious night increase of mesopelagic biomass was observed at JL7K, which was probably due to migrators from bathypelagic zone. Active carbon flux by DVM of zooplankton was estimated to be 0.23 mmol/(m2·d) at JL7K and 0.16 mmol/(m~2·d) at MA. The community structure analysis showed that calanoid copepods, cnidarians and appendicularians were the main contributors to DVM of mesozooplankton at both sites. We also compared the present result with previous studies of the two ecosystems,and suggested that the DVM of mesozooplankton was more homogeneous within the WPWP and more variable within the NPSG, though both ecosystems showed typically extremely oligotrophic conditions. The different diel vertical migration strength of mesozooplankton between NPSG and WPWP implied different efficiency of carbon pump in these two ecosystems.     

南海中部深海海山汁蛇尾属(Ophiurothamnus)二新记录种(蛇尾纲,棘蛇尾科)

通过对2018年4—5月在南海中部黄岩海山采集的蛇尾样品进行形态学分类研究,鉴定发现棘蛇尾科Ophiacanthidae汁蛇尾属Ophiurothamnus两个新记录种:(1)双环汁蛇尾Ophiurothamnus discycla (H. L. Clark, 1911);(2)短简汁蛇尾Ophiurothamnus clausa (Lyman, 1878)。本文分别对这两个新记录种的外部形态特征和内部骨骼进行了描述,并与相似种进行了分类学讨论。