【作者】 丁军军；

【导师】 徐奎栋；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋生物学， 2012， 硕士

【摘要】 鞭毛虫和纤毛虫在海洋微食物环和经典食物链间的能量流动中起着重要的枢纽作用，但其在水母暴发过程中的作用仍然不明。本研究基于2011年春季以及夏季黄东海973专项航次，通过荧光染色技术和定量蛋白银法（QPS）研究了水母频发区—黄海和东海海域12个断面、68个站位（26°30–37°00N，120°30–125°30E）的鞭毛虫和纤毛虫的群落结构和时空分布特点，并对其与水母的发生关系进行了初步探讨。研究显示，春、夏季的微型鞭毛虫丰度均以近岸水域为最高，向外海递减；高值区皆集中在长江口以及南黄海近岸区域，推测长江巨量径流所携带的大量丰富的有机物质能够直接或间接为鞭毛虫提供食物和营养物质，导致鞭毛虫的丰度较高。夏季随着长江冲淡水影响范围的扩大，其高值区扩展至长江口L断面离岸区域。垂直分布上，春季鞭毛虫的丰度高值区分布在表层及温跃层底部附近，夏季鞭毛虫丰度及生物量的高值区集中在表层。夏季总微型鞭毛虫的丰度（779±866cells/ml）和生物量（20.26±20.53g C/L）较春季（604±405cells/ml，19.98±17.68g C/L）略高，夏季异养微型鞭毛虫所占比例增大，显示水体的异养程度加大。在检获并鉴定的51种纤毛虫中，无壳类有19属35种，砂壳类12属16种。两季节均以无壳纤毛虫占绝对优势，约达总丰度的95%，贡献总生物量的90%。纤毛虫丰度的水平分布与鞭毛虫正相反，以近岸水域较低，高值区多位于中陆架和外陆架海区；水体表层及10m水层分布的纤毛虫达总丰度的80%。统计分析表明，纤毛虫的分布与盐度呈显著负相关，与温度呈显著正相关，其群落分布与水团的划分较为吻合，且春夏群落结构变动明显，推测黄东海不同季节水团影响而引起的温度、盐度以及叶绿素a分布格局的变化是影响黄东海纤毛虫分布的重要因素。夏季整体表层纤毛虫丰度和生物量（4812±5953cells/L、16.90±29.90gC/L）较春季（4258±4151cells/L、12.43±24.36g C/L）略高，但各断面变化不一致，水母未出现断面其纤毛虫丰度整体呈增加趋势，其增幅高达100%-200%，个别断面如断面I其纤毛虫丰度甚至增加一个数量级。而水母出现的断面纤毛虫丰度整体呈下降趋势，其中E、G、PN断面的纤毛虫数量明显降低，夏季较春季分别减少约61%、65%、23%，仅个别断面略有增加，如段面C、L，但其增幅明显较水母未出现断面小。由此推测纤毛虫数量变化可能与水母的发生有直接关系，水母发生的断面由于水母的捕食等压力导致纤毛虫丰度较春季明显降低，纤毛虫数量的减少导致对鞭毛虫的摄食压力降低，鞭毛虫数量增加。而未监测到水母的断面的纤毛虫生存压力较小，从而有机会快速繁殖达到较高的丰度值。由此可见，水母作为浮游生态系统的顶级捕食者，可通过营养级联效应对微小型浮游动物群落产生影响。本研究突破传统的Uterm hl氏沉淀-倒置显微镜镜检法，采用定量蛋白银法对纤毛虫群落结构以及多样性进行研究。与已有的浮游纤毛虫研究相比，本研究检获的纤毛虫丰度明显高于以往相同海域的调查，以长江口邻近海域的调查数据为例，本研究结果较前人报道的结果高5倍左右。本研究显示，春季、夏季nano级纤毛虫对于丰度的贡献比例可分别高达39%和57%，可见小个体纤毛虫对于微小型浮游动物的贡献不可忽视。但传统的倒置显微镜镜检法由于分辨率低，可能遗漏对nano级纤毛虫的检获，而定量蛋白银染色技术分辨率相对较高，对个体较小的纤毛虫不易漏检，并可对纤毛虫进行较为细致的分类鉴定工作，从而给出更为丰富的群落结构信息。更多还原

【Abstract】 Nanoflagellates and ciliates, the key intermediates between the ‘microbial’ andthe ‘classical’ pathway, play an important role in nutrient and carbon cycling inpelagic systems. However, their role during jellyfish bloom remains unexplored. Weinvestigated the changes of the community structure and distribution of planktonicnanoflagellates and ciliates based on samples collected from the12transects in theYellow Sea and East China Sea in April and August of2011. The nanoflagellates andciliates were studied using DAPI epifluorescence microscopy and the quantitativeprotargol stain, respectively. The potential relationship between the nano-andmicrozooplankton and the jellyfish (Rhopilema esculentum Kishinouye) occurrence insummer was discussed.Our study showed that the abundance of nanoflagellates was high in the coastalarea and decreased towards the offshore area. The high abundance was likelyattributed to the distribution of high value of nutrients in this area, which wasinfluenced by Changjiang River diluted water, and was extended to the offshore areaalong the transect L with the extension of the influences of the Changjiang Riverdiluted water in summer. Vertically, nanoflagellates were mainly distributed in thesurface and near the bottom layers of water. Compared with those in spring (604±405cells/ml,19.98±17.68g C/L), the total abundance and biomass of nanoflagellatesslightly increased in summer (779±866cells/ml,20.26±20.53g C/L), with thecontribution of heterotrophic nanoflagellates increased from28%in spring to37%insummer.Among the51ciliate taxa identified,35taxa of aloricate ciliates belonging to19genera contributed to95%of total ciliate abundance, and tintinnids (12genera,16taxa) contributed to the rest. Different from that of nanoflagellates, the abundance ofciliates increased from the inshore to offshore area. Vertically, ciliates in the surfacelayer contributed up to80%of the total abundance and abruptly decreased below the30m depth. Statistical analyses showed that the species number was significantlypositively correlated with temperature and negatively with salinity and water depth.The distribution of ciliate community was consistent with the water mass, with anobvious change from spring to summer. We indicate that the change in the pattern oftemperature, salinity and Chl a affected by different water mass in spring and summerwas the major factors resulting in the distribution of ciliates in the Yellow Sea and East China Sea. Compared to those in spring (4258±4151cells/L and12.43±24.36gC/L), the overall ciliate abundance and biomass (4812±5953cells/L and16.90±29.90g C/L) slightly increased in summer. The ciliate abundance at transects where therewas no jellyfish observed increased by about100%-200%from spring to summer,while certain transects such as transect I got a sharp increase by10times in ciliateabundance. By contrast, at transects where jellyfish occurred there was a tendency ofciliate decrease in abundance, and consequently resulted in the increase ofnanoflagellates. Our study indicates that jellyfish as top predators may cause directand indirect changes to nano-and microzooplankton through cascading effects. Theobvious decrease of ciliates at the transects E、G and PN was likely attributed to thepredation pressure from increasing jellyfish.In addition, the quantitative protargol stain (QPS) method yielded a highertaxonomic resolution and higher abundance for ciliates than the traditional Uterm hlmethod. For example, the ciliate abundance detected from the Changjiang Riverestuary was almost5times higher than previously reported. We indicated that thetraditional Uterm hl method would underestimate the abundance of small ciliates,especially the nano-ciliates which contributed to about39%and57%of the totalciliate abundance in spring and summer, respectively. The QPS method could providemore details about species-abundance information via taxa identification andclassification with much higher taxonomic resolution.更多还原