2013年夏季西南印度洋表层浮游动物群落分布格局

本研究基于2013年夏季“大洋一号”船大洋第30航次西南印度洋海区科学考察走航线路,对西南印度洋21°S到38°S海域表层浮游动物群落进行连续采样调查,研究了该海域表层中型浮游动物群落结构和物种多样性及空间分布格局。结果显示,研究海域表层中型浮游动物群落组成包括:桡足类、磷虾类、端足类、十足类、介形类、毛颚动物、被囊类、异足类、翼足类、刺胞动物及多毛类等11大类,总计50属69种;优势类群为桡足类(69%)和磷虾类(27%)。多样性指数随经度和纬度的变化特征:H′、D多样性指数及J均匀度指数随纬度的升高均呈下降趋势;在经度梯度上,几种多样性指数也大致呈现出东高西低的趋势。聚类分析表明,研究区可大致以36°S附近为界划分为南部和北部两大类群,分别以北部桡足类(平均粒径小),南部磷虾类(平均粒径大)Euphausia属为优势群落。群落相似性结果反映出,南部类群与南极克罗克海峡和南极长城湾水域群落,北部类群与西北印度洋海域群落的联通性不高。

Distribution patterns of zooplankton community structure of the surface water from Southwest Indian Ocean in the summer of 2013

Surface zooplankton samples were collected between 21°S and 38°S during the Dayang-1 scientific cruise in Southwest Indian Ocean in summer of 2013. By using zooplankton community structure analysis and clustering method, the distribution pattern of community structure and biodiversity of this region were explored. The results showed that the zooplankton species belonged to 69 species of 50 genus, including copepods, euphausiids, amphipods, decapods, ostracods, chaetognaths, tunicates, heteropods, pteropods, cnidarians, polychaetes and etc. In terms of abundance, copepods and euphausiids accounted for the largest percentages (69% and 27%, respectively). The variation of H′, D, J biodiversity indices with the latitude accorded a linear trend, i.e. most biodiversity indices decreased with the increase of latitude. In contrast, a binomial relationship was found between the biodiversity indices and longitude. Most biodiversity indices increased with the longitude. The clustering results showed that northern and southern zones could be distinguished by the latitude boundary around 36°S, with the predominant species of copepods (small particle) in northern zone and euphausiids (large particle) in southern zone respectively. Moreover, the similarity of species composition indicated that the spatial connectivity of zooplankton communities was week between the southern zone and Crocker Strait or Great Wall Bay in Antarctica, as well as between the northern zone and Northwest Indian Ocean.