Physiological and ecological study on deep-sea zooplankton

本研究填补了我们对西亚北极太平洋Oyashio区中层和深层中/大型浮游动物生理和生态特征认识的差距。在3000米以下的海域进行了季节性的垂直封网采样，以阐明浮游动物优势类群的垂直分布和生活史模式。取活体标本测定耗氧率和电子转移系统（ETS）酶活性。核酸（RNA，DNA）测定作为各种浮游动物的营养和生长条件的指标。主要研究结果如下：1.中/深海区数量优势的中浮游动物-分类单元代表种（介形类、桡足类）的生活史模式具有全年繁殖、世代周期长（1-2年）的特点。他们中的一些人表现出个体发育的垂直迁移模式（向上迁移的年轻阶段）。对中层/深海区具有滞育期的跨层大型食草桡足类的生活史进行了全面评价。2.中层/深层浮游动物（主要是桡足类）的耗氧率通常是上层浮游动物的一半（注：在此比较中，温度和体重的影响均被排除）。区带间桡足类滞育时的耗氧率仅为摄食时的30%。ETS检测结果进一步支持了上述结论。3.从RNA/DNA比值判断，中/深海桡足类的营养/生长条件不如海洋桡足类（注：去除了体重的影响，但由于资料不足，目前还不能去除温度的影响）。大部分结果将被公布。

This study was undertaken to fill the gap of our knowledge about physiological and ecological characteristics of meso/macro zooplankton in mesopelagic and bathypelagic zones of the Oyashio region, western subartic Pacific. Seasonal samplings with vertical closing nets were made down to 3000m to elucidate vertical distribution and life cycle patterns of dominant zooplankton taxa. Live specimens were retrieved for measuring oxygen consumption rates and enzyme assay of electron-transfer-system (ETS). Nucleic acids (RNA, DNA) were determined as an index of nutritional and growth conditions of various zooplankton. The outcome of the study can be summarized as follows ;1.Life cycle modes of representative species of numerically dominant mesozooplankto taxon (ostracods, poecilostomatoid copepods) in the meso/bathypelagic zones were characterized by year-round reproduction and long generation times (1-2 years). Some of them exhibited an ontogenetic vertical migration pattern (upward migration at younger stages). Life-cycles of interzonal large grazing copepods which have diapause phase in meso/bathypelagic zones were fully evaluated. Most of the results were published.2.Oxygen consumption rates of meso/bathypelagic zooplankton (largely copepods) were typically one-half the rates of epipelagic counterparts (note : the effects of temperature and body mass were all removed in this comparison). Of interzonal copepods, oxygen consumption rates of the specimens in diapause were shown to be as low as 30% of the rates at active feeding. The conclusion was further supported by the results of ETS assay. Part of the results was published.3.As judged by RNA/DNA ratios, nutritional/growth conditions of meso/bathypelagic copepods appeared to be less optimal as compared with epipelagic counterparts (note : the effect of body mass was removed, but the effect of temperature could not be removed at present because of the lack of information). Most of the results are to be published.