南海北部陆架斜坡海域夏季浮游动物群落的空间分布

根据2015年7-8月南海北部陆架斜坡海域的浮游动物垂直分层采集资料,对该海域浮游动物的种类组成、优势种、丰度和生物量及群落结构的空间分布等进行了研究。样品利用Multinet浮游生物连续采样网采自0~200 m,200~350 m,350~450 m,450~600 m,600~750 m等5层。该次调查共发现浮游动物468种(类),其中以0~200 m水层种类最丰富,600~750 m水层最贫乏,种类数总体随水深的增加而减少,但在350~600 m水层部分站位出现了回升。浮游动物种类组成垂直变化较明显,各水层均有出现89种共有种,占总种类数的19.02%;而单一水层出现的特有种(121种)占总种类数的25.85%。优势种有10种,角突隆剑水蚤(Oncaea conifera)为各水层的共有优势种,在不同水层还出现了特有优势种。浮游动物丰度和生物量平均为62.79个·m~(-3)和34.81 mg·m~(-3),总体呈现由表层向深层逐渐递减的分布趋势,但在350~600 m水层大部分站位也略有回升。聚类分析结果表明,该调查海域浮游动物大体分为3个群落,分别为0~200 m的上层水域群落、200~450 m的中上层水域群落和450~750 m的中下层水域群落。

Spatial distribution of zooplankton in continental slope of northern South China Sea in summer

According to the vertical sampling data on zooplankton in the continental slope of northern South China Sea in summer,2015,we examined the spatial distribution of species composition,dominant species,abundance,biomass and zooplankton commu nity structure.Zooplankton samples were collected by discrete Multinet at 0～ 200 m,200～ 350 m,350 ～450 m,450～ 600 m and 600 ～ 750 m of depths,respectively.The results show that a total of 468 zooplankton species were found,and the species richness was the highest at 0 ～200 m layer water,and was the lowest at 600 ～750 m layer water,but there was slight rebound in some stations at 350 ～ 600 m water layer.The zooplankton common species occurring at all water layers took up 19.02％ of the total species,while the endemic species occurring at just one water layer made up 25.85％ of the total species.There was obvious vertical variation in the zooplankton species composition.A total of 10 dominant species were observed,among which Oncaea conifera was the common species occurring at all water layers.Besides,some endemic dominant species occurred at each water layer.The average abundance and biomass of zooplankton were 62.79 ind ·m-3 and 34.81 mg·m-3,respectively.With increasing depth of water,zooplankton species richness decreased generally.Three communities were identified by clustering analysis.Group 1 contained samples collected at surface water (0 ～200 m) with average abundance of 228.68 ind ·m-3.Group 2 contained samples collected at upper-middle-layer water (200 ～450 m) with average abundance of 31.91 ind ·m 3.Group 3 contained samples collected at lower-middle-layer water (450 ～750 m) with average abundance of 10.61 ind ·m-3.