【作者】 张利永；

【导师】 周名江； 颜天；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋生物， 2007， 博士

【摘要】 本文从赤潮发生前的现场模拟实验、赤潮发生时的现场培养实验和赤潮发生过程中的现场调查等方面,较为系统地研究了东海大规模赤潮对微型浮游动物群落结构的影响。2005年长江口及邻近海区赤潮发生前,赤潮973MC2005-03航次在本海区进行了综合调查,期间分别于4月27日、5月4日和5月8日,在zzf1、zc18a和ra5三个站位利用现场船基培养的方法,研究了添加到赤潮密度10⁶ cells L-1的东海原甲藻（Prorocentrum donghaiense）对微型浮游动物群落结构的影响。结果发现,赤潮密度的东海原甲藻对小型无壳纤毛虫的种群数量影响较大,而对中大型砂壳纤毛虫的影响较小,从而使得微型浮游动物群落有向中大型砂壳纤毛虫演替的趋势。在zzf1站位,小型无壳纤毛虫占绝对优势,添加东海原甲藻72 h后,优势种由管游虫（Cyrtostrombidium sp.）演替为另一种小型无壳纤毛虫急游虫4（Strombidium sp.4）;在以中型砂壳纤毛虫百乐拟铃虫（Tintinnospsis beroidea）为优势种的zc18a站位,仍然是以此为优势种,但其在群落中的优势度更加明显;ra5站位也是以小型无壳纤毛虫为主,添加东海原甲藻72 h后,其群落结构由急游虫2（Strombidium sp.2）向中大型砂壳纤毛虫纤毛虫百乐拟铃虫和亚速岛网纹虫（Favella azorica）演替。不同站位微型浮游动物群落结构变化的差异与其本身的群落结构组成有一定关系,也与浮游植物的群落组成有关。zzf1和ra5站位实验组中微型浮游动物的总丰度和总生物量都低于对照组,而zc18a站位变化不明显,这是由于前两个站位实验组中的优势种管游虫（zzf1站位）和急游虫2（ra5站位）的丰度和生物量迅速下降,而zc18a站位实验组的优势种百乐拟铃虫的丰度和生物量比较稳定造成的。2005年长江口及邻近海区赤潮发生时,赤潮973 MC2005-04航次在本海区进行了综合调查,期间分别于5月26日、5月28日、5月28日和5月29日,在xzm1、srb、sra1和hb8a四个站位利用现场培养的方法,研究了东海大规模赤潮对微型浮游动物群落结构的影响。结果发现,东海大规模赤潮对微型浮游动物群落结构的影响与赤潮藻的密度密切相关:xzm1、srb和sra1站位是赤潮区,两种赤潮藻的总密度分别为,1.3×10⁶ cells L-1、1.8×10⁶ cells L-1和5.6×10⁶ cellsL^-1,而hb8a站位位于非赤潮区,两种赤潮藻的总密度仅为5×10⁵ cells L^-1;实验进行72 h后,在以大型砂壳纤毛虫网纹虫和筒壳虫（Tintinnidium sp.）为主的xzm1、srb和sra1站位,仍然是以这些大型砂壳纤毛虫为主,且其在群落中的百分比显著增大,尤其在赤潮藻密度最高的的sra1站位,这种演替趋势表现的最明显;而在以小型无壳纤毛虫急游虫2为主的hb8a站位,微型浮游动物群落向中型砂壳纤毛虫真丁丁虫（Eutintinnus sp.）演替。培养过程中微型浮游动物总丰度的变化以及总生物量的变化都与赤潮藻的密度密切相关:赤潮藻密度较低的xzm1站位和srb站位变化不大;赤潮藻密度较高的sra1站位则快速下降;而非赤潮区的hb8a站位呈快速上升的趋势。以上结果进一步表明东海大规模赤潮能使微型浮游动物群落向中大型砂壳纤毛虫演替。在2006年4月18日-5月30日,赤潮973项目MC2006航次在长江口及其邻近海区围绕东海原甲藻和米氏凯伦藻赤潮进行了综合调查。为了研究该过程中微型浮游动物群落结构的变化,我们在南北5个断面共计21个站位进行了取样,样品涉及赤潮发生前期、发生期和消退期。本次调查共发现纤毛虫66种,其中砂壳纤毛虫有8属37种,寡毛类无壳纤毛虫25种,另外还有前口类3属4种。在赤潮发生前之前,小型无壳纤毛虫的丰度普遍较高,平均值为1574 ind L^-1,而中大型砂壳纤毛虫的丰度普遍偏低,平均值仅为14 ind L^-1;赤潮发生以后,在大多数站位小型无壳纤毛虫的丰度出现不同程度的下降,平均值降为171 ind L^-1,而中大型砂壳纤毛虫的丰度出现一定程度的上升,平均值增至216 ind L^-1。赤潮消退时,小型无壳纤毛虫丰度的平均值降为109 ind L^-1,而中大型砂壳纤毛虫的丰度继续增长,变为401 ind L^-1。不同微型浮游动物百分比的统计结果也表明:微型浮游动物群落由小型无壳纤毛虫向中大型砂壳纤毛虫演替的趋势:小型无壳纤毛虫在群落中百分比的平均值由赤潮发生前的62 %变为赤潮发生时的32 %,至赤潮消退时又降为15 %;而中大型砂壳纤毛虫百分比的平均值从赤潮发生前的10 %变为赤潮发生时的24 %,至赤潮消退时增至50 %。典型站位za3、za5、zb7和zb9的结果再次表明了赤潮发生过程中微型浮游动物群落由小型无壳纤毛虫向中大型砂壳纤毛虫演替的趋势。由以上赤潮发生前的现场模拟实验、赤潮发生时的现场培养实验和赤潮发生过程中的现场调查的结果均可见,东海大规模赤潮可以改变微型浮游动物的群落结构,呈现由小型无壳纤毛虫向中大型砂壳纤毛虫演替的趋势,进而有可能影响中大型浮游动物等摄食者的种群数量和群落结构,最终可能会影响整个海洋生态系统的结构和功能。更多还原

【Abstract】 Based on shipboard inoculation experiment, shipboard incubation experiment and field survey during the large-scale HAB （Harmful algal blooms） in the East China Sea, the effects of large-scale HAB in the East China Sea on microzooplankton community structure were studied in the present paper.Before the large-scale HAB in the East China Sea, to study the effects of simulated HAB on microzooplankton community structure, shipboard Prorocentrum donghaiense inoculation experiments (at about 106 cells L^-1, equivalent to bloom density) were carried out at stations zzf1, zc18a and ra5 in the East China Sea on 27th April, 4th May and 8th May 2005, respectively. The results showed that P. donghaiense at a density of 106 cells L^-1 could affect the abundance of small-sized aloricate ciliates, but had no significant effect on medium- and large-sized tintinnids, which thereby led to a community succession toward medium- or large-sized individuals. At station zzf1, the microzooplankton community initially dominated by the small-sized aloricate ciliate Cyrtostrombidium sp. was dominated by another small-sized aloricate ciliate Strombidium sp.4 after adding P. donghaiense for 72 h. At station zc18a, the microzooplankton community initially dominated by medium-sized tintinnid Tintinnopsis beroidea was still dominated by the same species and its ratio in the microzooplankton community increased noticeably after adding P. donghaiense for 72 h. At station ra5, the microzooplankton community initially dominated by the small-sized aloricate ciliate Strombidium sp.2. changed dramatically and was dominated by T. beroidea and large-sized tintinnid Favella azorica after adding P. donghaiense for 72 h. The differences aong microzooplankton community succession of the three stations were closely related to both microzooplankton and phytoplankton community compositions. Compared to the control, the total abundance and biomass of microzooplankton in experimental groups decreased dramatically at stations zzf1 and ra5 due to the reduction of their dominant species Cyrtostrombidium sp. and Strombidium sp.2, whereas no significant variation was found at station zc18a due to the steady abundance of dominant species T. beroidea.During the large-scale HAB of P. donghaiense and Karenia mikimotoi in the Changjiang River estuary in summer 2005, the effects of the HAB on microzooplankton community were studied at 4 stations xzm1, srb, sra1 and hb8a, on 26th , 28th , 28th and 29th May, respectively. The results showed the actual effects of HAB were closely related to the concentration of the HAB algae. The concentration of the two HAB algae was 1.3×10⁶ cells L^-1、1.8×10⁶ cells L^-1 and 5.6×10⁶ cells L^-1 at stations xzm1, srb and sra1, respectively, however, it was only 5×10⁵ cells L^-1 at station hb8a. Cultured 72 h latter, HAB-stations xzm1, srb and sra1 formerly dominated by large-sized tintinnids Favella sp. and Tintinnidium sp. were still dominated by these two individuals, and their dominant degree in the microzooplankton community showed a significantly increasing trend, especially at the station sra1. In contrast, the non-HAB station hb8a formerly dominated by small-sized aloricate ciliates was dominated by medium-sized tintinnid Eutintinnus sp. The total abundance and biomass of microzooplankton were strongly affected by the density of HAB algae too, which increased a little at station xzm1, changed scarcely at station srb, decreased dramatically at station sra1, while increased considerably at station hb8a, respectively. The results further showed that large-scale HAB in the East China Sea could make the microzooplankton community succession from small-sized aloricate ciliates to medium and large-sized tintinnids. The community succession of microzooplankton during the large-scale HAB of P. donghaiense and K. mikimotoi in the East China Sea was studied based on the water samples taken from 21 stations in summer 2006. A total 66 species, includingTintinnina 37 species, Oligotrichina 25 species and Prostomatida 4 species were found in the survey area. Before the HAB of P. donghaiense and K. mikimotoi, the abundance of small-sized aloricate ciliates was high at almost all stations and the average value was 1574 ind L^-1. On the other hand, the abundance of medium- and large-sized tintinnids was low at most stations and the average value was only 14 ind L^-1. When the HAB broke out, the abundance of small-sized aloricate ciliates showed a decreasing trend at most stations and the average value reduced to 171 ind L^-1. In contrast, the abundance of medium- and large sized tintinnids showed an increasing trend and the average value increased to 216 ind L^-1. During the decay of the HAB, the abundance of small-sized aloricate ciliates continued to decrease and the average value reduced to 109 ind L^-1, whereas, that of medium- and large-sized tintinnids has been still keeping on rising and the average value increased to 401 ind L^-1. The results of the ratios of different ciliates in microzooplankton community also showed that large-scale HAB could make microzooplankton community succession from small-sized aloricate ciliates to medium and large-sized tintinnids. Before the HAB, the average value of the ratios of small-sized aloricate ciliates was 62 %, it became 32 % with the HAB breaking out and it reduced to 15 % during the decay of the HAB. In contrast, the average value of the ratios of medium- and large sized tintinnids was 10 % before the HAB, it became 24 % when the HAB broke bout and it rised to 50 % during the decay of the HAB. The results of typical stations za3, za5, zb7 and zb9 also showed that microzooplankton community structure changed from small-sized aloricate ciliates to medium and large-sized tintinnids during the HAB.From the above three studies, it can be seen that the large-scale HAB in the East China Sea could make microzooplankton community succession from small-sized aloricate ciliates to medium and large sized tintinnids which implied that the large-scale HAB might affect the abundance and community structure of the organisms at the higher trophic levels, ultimately, might affect the structure and function of marine ecosystem of the East China Sea.更多还原