南黄海绿潮对浮游动物优势种种群补充、食物组成及群落结构的影响

Zooplankton, as a key link of the marine ecosystem, is highly susceptible to various environmental conditions due to its weak swimming ability and small size. The large-scale green tides prevailing in the southern Yellow Sea can change the structure of nutrients and the state of phytoplankton and in turn affect zooplankton species. Based on this, during the development process of green tides in the southern Yellow Sea, in situ investigation of zooplankton and its related influencing factors will be carried out, meanwhile, the reproduction of dominant zooplankton species under different environmental conditions will be tested by ship-based experiment. Ultimately, the impact of green tides on zooplankton will be evaluated at population and community levels: Find out the difference in the potential population recruitment of dominant zooplankton species and the oil sac volume of the fifth copepodite (C5) of C. sinicus and adult female of P. parvus under different coverage of green algae; analyze in situ diets of dominant species under different environmental conditions by the high-throughput sequencing technique and then compare food composition of C. sinicus and P. parvus at different time scales combining the stable isotope technique, which can reveal the effect of green tides on the feeding selectivity of zooplankton. On the basis of the changes of reproduction, energy storage and feeding of the dominant zooplankton species, the potential impact of green tides on the population recruitment and maintenance of zooplankton in the southern Yellow Sea will be dissected. Combined with historical data, the project will clarify the variations of zooplankton community structure and its environmental driving mechanism which can provide a scientific basis for the disaster reduction and relief of green tides.

浮游动物是海洋生态系统的关键一环，其游泳能力弱，个体小，在海洋中极易受到各种环境条件的影响。南黄海持续暴发大规模绿潮，能够改变水体营养盐结构和浮游植物现状，进而影响浮游动物。基于此，本项目将在南黄海绿潮发生发展过程中进行浮游动物及影响因素的现场调查，并通过船基实验研究不同条件下浮游动物优势种繁殖的差异，以期在种群和群落水平上评估绿潮对浮游动物的影响：查明不同绿藻覆盖度下浮游动物优势种种群潜在补充及中华哲水蚤C5期幼体和小拟哲水蚤雌性成体油囊体积差异；利用高通量测序技术分析不同环境条件下浮游动物优势种食物组成，结合稳定性同位素方法比较不同时间尺度下浮游动物食物组成的异同，揭示绿潮对浮游动物选择性摄食的影响；基于浮游动物优势种繁殖、能量储存和摄食的变化剖析绿潮发生时种群的补充与维持机制，结合历史资料，阐明绿潮暴发时浮游动物群落结构的变化及其环境驱动机制，为绿潮防灾减灾提供科学依据。

2007年以来，南黄海持续暴发大规模绿潮。绿潮藻最早出现在江苏近岸的苏北浅滩，之后在风力和海流等作用下进入黄海中部，规模不断扩大。.本项目分析了2009-2012年江苏近岸浮游动物优势种变化趋势，发现优势种变化较小，中华哲水蚤、强壮滨箭虫、真刺唇角水蚤和磷虾幼体为共有优势种（类）。与上世纪80年代资料进行对比，发现绿潮暴发并未对江苏近岸浮游动物优势种组成产生显著影响；分析发现，2009年和2010年绿潮藻运移轨迹存在差异，江苏近岸浮游动物分布趋势与之对应；江苏近岸大型藻分布成片区存在真刺唇角水蚤、长额刺糠虾、洪氏纺锤水蚤和虫肢歪水蚤等的丰度高值区，因此，成片分布大型藻对浮游动物分布影响有限；.黄海中部大规模绿潮藻聚集区网采浮游动物优势种在绿潮暴发前、暴发初期和暴发10年后浮游动物优势种无显著变化：中华哲水蚤、强壮滨箭虫、太平洋磷虾和细足法虫戎为大网调查优势种，拟长腹剑水蚤、小拟哲水蚤、强额拟哲水蚤、沃氏纺锤水蚤、中华哲水蚤和强壮滨箭虫为中网调查优势种；中华哲水蚤分布主要受水团、海流、海洋锋等的影响，有大型藻覆盖的海区，中华哲水蚤丰度亦较高，绿潮暴发前后，相同站位浮游动物优势种丰度并无明显升高或降低的趋势。同样，在绿潮暴发后，中华哲水蚤油囊体积百分数与以往调查并无明显区别，整体来看，绿潮暴发对南黄海浮游动物群落无显著影响；.在江苏近岸和黄海中部大型藻覆盖区存在一定数量的微观繁殖体，但通过高通量测序，并未在中华哲水蚤肠道内含物中发现绿藻微观繁殖体。分析了江苏近岸至长江口以及黄海中部3种常见浮游动物的线粒体DNA全长，为后续研究提供数据参考；.在调查过程中发现，绿潮藻上附生丰度较高的端足类藻钩虾，其通过啃食作用可以消除绿藻，但啃食过程中也可增加水体微观繁殖体的数量；另外在黄海底栖拖网中发现，两种常见蛇尾对底栖钩虾有明显的摄食行为，南黄海藻钩虾随藻体沉降，可能对底栖生态系统产生影响。