【作者】 郑珊；

【导师】 孙松； 孙晓霞；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋生态学， 2013， 博士

【摘要】 通过室内受控实验以及现场模拟实验，对水母暴发与浮游植物群落的相互影响进行了研究。首先是从下行控制的角度出发，研究水母是否能够对浮游植物进行直接摄食。通过海月水母水螅体、碟状体和水母体对中肋骨条藻和东海原甲藻的摄食活动的研究表明，水螅体和碟状体对中肋骨条藻和东海原甲藻的摄食率随藻细胞密度的升高而升高。碟状体的摄食率高于水螅体。经过藻类饵料适应处理的水螅体对藻类的摄食率会有显著增加。其次，从浮游植物对水母的影响的角度，研究不同类型的浮游植物对水母的生长的影响。实验结果表明，对于刚刚释放的海月水母碟状体，中肋骨条藻和东海原甲藻对碟状体的生长无贡献，而亚心形扁藻和夜光藻对碟状体前12天的生长有一定贡献，但在12天之后无法维持碟状体的进一步生长发育。卤虫则能支持碟状体在12天内持续生长并发育成水母体，说明对于海月水母碟状体，动物性饵料明显优于植物性饵料。最后，从上行控制角度，研究了水母的代谢及分解过程以及该过程中浮游植物群落结构的变化。实验结果表明，沙海蜇在代谢过程在短时间内大量消耗水体中的DO，使水体出现低氧和轻度酸化。代谢过程释放出大量营养盐，使水体中的DIN浓度在24h内增加为原来的12倍，DIP浓度增加了40多倍，进而引起水体中叶绿素a浓度的增加。沙海蜇在分解过程使水体表现出明显的低氧(缺氧)和酸化现象。沙海蜇生物量越大，分解时间越长，对水体的改变程度越明显。沙海蜇分解过程还释放出大量的营养盐并改变原有的营养盐结构，可以刺激甲藻和绿藻的生长，甚至引发藻华，进一步引起纤毛虫的丰度剧增。更多还原

【Abstract】 The interaction of jellyfish blooms and phytoplankton community was studiedvia laboratory controlled experiments and in situ experiments.First, we studied the top-down regulation of phytoplankton by jellyfish viafeeding rate definition. The effects of different microalgal species and cell densitieson the feedings of polyps, ephyrae and medusae of Aurelia sp.1under controlledlaboratory conditions were investigated. Two species of microalgae, Skeletonemacostatum and Prorocentrum donghaiense, were used. With the increasing ofmicroalgal cell desities, the ingestion rates (IR) of polyps and ephyrae increased whilethe clearance rates (CR) decreased, and the IR of ephyrae were higher than those ofpolyps. The adaption of microalgae made IR of polyps increased about ten times.Second, we evaluated the effects of different microalgal species on the growth ofnewly released Aurelia sp.1ephyrae under the controlled laboratory conditions.Results showed that newly released ephyrae can utilize some species of microalgaefor growth in the earliest development stage. Chain diatom Skeletonema costatum anddinoflagellate Prorocentrum donghaiense could not be utilized by ephyrae, while Noctiluca scintillans and chlorophyta Platymonas subcordiformis could support thegrowth for the ephyrae for the first12days. However, the ephyrae fed withphytoplankton could not develop to medusae.Last, we studied the bottom-up regulation of phytoplankton by jellyfish duringrespiration and decomposition. Results suggested that the seawater acidification andhypoxia occurred during the respiration of Nemopilema nomurai in24hours.Meanwhile, inorganic nutrients regenerated by N. nomurai greatly increased theconcentrations of DIN and DIP in the seawater, which led to the increase ofchlorophyll a concentration.The decomposition of N. nomurai led the seawater to significant oxygen deficitand acidification, and it got more severe when the biomass of N. nomurai was higher.Numerous inorganic nutrients were released to the seawater and the structure ofinorganic nutrients was greatly changed and dinoflagellates and chlorophyta bloomed.Furthermore, the abundance of ciliates increased due to the sufficient food.更多还原