摘要
于2004年8月1～6日对台湾海峡南部近岸的藻华过程进行了定点连续跟踪观测，用稀释法研究了浮游植物的生长率和小型浮游动物对浮游植物的摄食死亡率，同时运用高效液相色谱（HPLC）技术，分析了浮游植物不同光合色素类群的生长率和摄食死亡率．结果表明，观测期间处于藻华的消退期．8月1日时，浮游植物生物量（叶绿素a）和丰度分别为2．04μg／dm^3和2．99×10^5个／dm^3，主要优势种为尖刺伪菱形藻（Pseudo-nitzschia pungens）、冰河拟星杆藻（Asterionellopsis glacialis）和中肋骨条藻（Skeletonema costatum），8月6日时，浮游植物生物量和丰度分别减为0．37μg／dm^3和1．54×10^4个／dm^3；而蓝藻和甲藻的丰度和比例则呈现出逐渐增加的趋势，所占的比重分别从1日的0．04％和0．85％增加到6日的9．59％和41．97％．小型浮游动物主要由无壳纤毛虫、砂壳纤毛虫、红色中缢虫（Mesodiniumrubrum）和异养甲藻等类群组成，总丰度于8月2日达到最大值，为3640个／dm3，之后逐渐减少，6日时，仅为436个／dm^3．观测期间，小型浮游动物在群落组成上虽一直以无壳纤毛虫和异养甲藻为主，但在具体的类群结构上却表现出了一定的差异，30μm以下的无壳纤毛虫和异养甲藻总体呈下降的趋势，而红色中缢虫、砂壳纤毛虫和大于50pm的无壳纤毛虫总体呈增加的趋势．观测期间，浮游植物的生长率为0．40～0．91d^-1，小型浮游动物的摄食率为0．26～1．34d^-1，摄食率和生长率总体呈逐渐下降的趋势．结果还表明，小型浮游动物的摄食率与叶绿素a具有很好的相关性（R^2=0．89），对各光合色素类群的现存量和初级生产力均具有较高的摄食压力（分别为37．97％～82．24％和70．71％～281．33％），是藻华消亡的重要原因之一；此外，小型浮游动物对甲藻和蓝藻的避食行为，可能是观测期间由“硅藻”水华向“硅藻-甲藻”水华转变的重要原因之一．
To investigate the role of microzooplankton on algal bloom in coastal ecosystem, phytoplankton growth rate and mortality rate resulted from microzooplankton grazing and its effects on processes of algal bloom were measured using the dilution method in the Taiwan Strait during 1 to 6 August 2004. Meanwhile, pigment-specific growth of phytoplankton and grazing rate of microzooplankton were also studied using high-performance liquid chromatography （HPLC） on 3 August 2004. Results showed that processes of algal bloom was in decline during the survey, phytoplankton biomass （chl a） and abundance were 2. 04 μg/L and 2. 99 × 10^5 ind./dm^3, at beginning of the survey, respectively, with dominance of Pseudo-nitzschia pungens , Asterionellopsis glacialis , Skeletonema costatum , on 1 August; however, phytoplankton biomass（chl a） and abundance were only 0. 37 and 1. 54 × 104 ind/dm^3 on 6 August, respectively. For community structure of phytoplankton, abundance and percentage of cyanobacteria and dinoflagellate increased during the survey, from 0. 04% and 0. 85% on 1 August to 9.59% and 41.97% on 6 Augst, respectively. Microzoopankton was mainly composed of aloricate ciliates, loricate ciliates, Mesodinium rubrum and heterotrophic dinoflagellates, the highest abundance was up to 3 640 ind./dm^3 on 2 August, the lowest only 436 ind./dm^3 on 6 August. During the observation, although aloricate ciliates and heterotrophic dinoflagellates were always the main components of microzooplanton, the community structure of microzooplanon showed some changes. The percentage of heterotrophic dinoflagellates and aloricate ciliate with smaller than 30 m declined during the survey, however, Mesodinium rubrum, loricate ciliates and aloricate ciliates biger than 50 m increased. Growth and mortality rates of phytoplankton were 0. 40-0. 91 d^-1 and 0. 26-1.34 d^-1 during the survey, respectively. Both growth and mortality rates of phytoplankton declined during the survey. The results also showed that there was a significantly positive linear correlation between microzooplamkton grazing rates and chlorophyll a （R^2=0. 89）. Pigment-based data showed significant gazing pressure on biomass and productivity of different groups （37. 97% -82.24 % and 70. 71% -281.33 % respectively）. Above results suggested that microzooplankton gazing was important factor for controlling algal bloom. Avoiding grazing of microzooplankton on cyanobacteria and dinoflagellate may be one of the reasons for phytoplankton community succession, from diatom-dominated to diatom and dinoflagellate-dominated community during the survey in the Taiwan Strait.
出处
《海洋学报》
CAS
CSCD
北大核心
2006年第5期107-116,共10页
基金
国家自然科学基金(40376043
40331004)
教育部新世纪优秀人才培养计划资助
关键词
小型浮游动物
摄食率
生长率
藻华
台湾海峡
microzooplankton
grazing rate
growth rate
algal bloom
Taiwan Strait
