摘要:
根据IONESS系统对浮游动物的分层采样结果,研究浮游介形动物的昼夜垂直移动.浮游介形类存在着整个类群的昼夜垂直移动,白天其丰度最大值记录于200～300m层,并往上层水域递减,而夜间则明显往上层密集,丰度最大值提升至50～100m层;就物种多样性而言,由于工作水层(0～1000m)以深水层的众多种类于夜间上升至1000m以浅水层,导致工作水层内总种数由白天的49种剧增至夜间的78种,增幅达60%,各分层的种类数都有较明显的增加,750～1000m层的增幅最大,达150%,其次为50～100m层(增幅达125%);各种浮游介形类有不同的昼夜垂直移动模式,但绝大多数种类属于夜间上升型,少数种类属于不敏感类型,极少数种类却具夜间下降的移动特点.浮游介形类虽具明显的昼夜垂直移动,但这一变动往往局限于一定水深范围,从而反映出介形类的层状分布特点,可划分为广深分布型、上层分布型、中层分布型和下层分布型.
Abstract:
The diurnal vertical migration of planktonic Ostracoda is studied based on the analysis of stratified samples of zooplanktons in the IONESS system. The whole taxa of planktonic Ostracoda migrates vertically and diurnally, its greatest abundance by day occurs at 200~300 m layer and decreases upward and at night occurs at 50~100 m layer but increases upward. Numerous species at the layers lower than the working layer ( 0~1 000 m) migrate upward at night to the layers shallower than 1 000 m. As a result, the total number of species in the working layer in creases sharply from 49 species by day to 78 species at night, with an increase amplitude of 60%. The number of species increases rather distinctly at various layers, firstly at the layer of 750~1 000 m with an amplitude of 150% and secondly at the layer of 50~100 m with an amplitude of 125%. Different planktonic Ostracoda takes different mode of diurnal vertical migration, agreat majority of species take the mode of upward migration at night, less number of species take insensitive mode and a fewer number of species take the mode of downward migration at night. The diurnal vertical migration of planktonic Ostracoda, which is distinct in this regard, is restricted in a certain water depth, demonstrating its features of stratified distribution. Ostracoda may be classified into four modes of distribution, namely, eurybathy distribution mode, upper layer distribution mode, mid-layer distribution mode and lower-layer distribution mode.
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