渤海湾近岸海域浮游纤毛虫丰度和生物量的季节变化

Seasonal Variations of Planktonic Ciliates in the Coastal Area of the Bohai Bay

中文关键词: 浮游纤毛虫  丰度  生物量  季节变化  渤海湾

英文关键词: Planktonic ciliate  Abundance  Biomass  Seasonal variation  Bohai Bay

中文摘要:

      2015年春季(5月)、夏季(7月)和秋季(9月)在渤海湾近岸海域进行浮游纤毛虫丰度和生物量的调查。浮游纤毛虫丰度、生物量及种类组成均表现出明显的季节变化。春、夏和秋季纤毛虫的平均丰度分别为(1016±868)、(2011±1327)和(2456±1776) ind./L，平均生物量分别为(1.91±2.53)、(5.78±4.45)和(3.11±2.40) μg×C/L。3个季节砂壳纤毛虫占纤毛虫丰度的比例平均为(26.7±23.3)%，夏季最高，为(43.4±25.1)%，秋季最低，为 (12.3±8.1)%。无壳纤毛虫和砂壳纤毛虫丰度和生物量的水平分布特点不同，无壳纤毛虫在3个季节中没有表现出明显的分布规律，在近岸和远岸都有丰度和生物量高值的出现；砂壳纤毛虫丰度和生物量则一般在近岸较高。3个季节共鉴定出砂壳纤毛虫 8属25种，其中，拟铃虫属(Tintinnopsis)种类最多。春季砂壳纤毛虫优势种为波罗的拟铃虫(Tintinnopsis baltica)、百乐拟铃虫(Tintinnopsis beroidea)和原始筒壳虫(Tintinnidium primitivum)；夏季砂壳纤毛虫优势种为妥肯丁拟铃虫(Tintinnopsis tocantinensis)、原始筒壳虫和厦门拟铃虫(Tintinnopsis amoyensis)；秋季砂壳纤毛虫优势种为原始筒壳虫。春季砂壳纤毛虫群落口径较小，为(31.5±2.5) μm，夏季和秋季较大，分别为(35.9±8.2)和(34.8±5.2) μm。夏季砂壳纤毛虫群落Shannon指数及Pielou指数均较春季和秋季大。本研究可为该海区浮游纤毛虫分布的长期变化、浮游生态系统的研究及渔业资源的发展提供基础数据。

英文摘要:

      Studies on the abundance and biomass of planktonic ciliates were conducted in the Bohai Bay during spring (May), summer (July) and autumn (September) of 2015. Fifteen stations were investigated in each season. One-liter sample of seawater from the surface layer was collected and fixed in 1% acid Lugol’s iodine solution. Water samples were pre-concentrated using the Utermöhl method and observed using an Olympus IX71 inverted microscope. The dimensions of the ciliates were measured and the cell volume of each species was estimated using appropriate geometric shapes. The carbon/volume ratio used to calculate the biomass was 0.19 pg C/µm3. The classification of tintinnids was based on previous literatures about taxonomy. The abundance and biomass of ciliates and the community structure varied in the three seasons. The average abundance of ciliates in the spring, summer and autumn was (1016± 868) ind./L, (2011±1327) ind./L and (2456±1776) ind./L respectively. The average biomass of ciliates in the spring, summer and autumn was (1.91±2.53) μg·C/L, (5.78±4.45) μg·C/L and (3.11±2.40) μg·C/L respectively. Tintinnids accounted for (26.7±23.3)% of the total ciliate abundance, and the value was the highest in the summer (43.4%±25.1%) and the lowest in the autumn (12.3%±8.1%). Aloricate ciliates and tintinnids exhibited different distribution patterns. The abundance and biomass of aloricate ciliates were higher in the coastal and offshore areas, while tintinnids tended to accumulate in the coastal area. Twenty five tintinnid species were identified that belonged to 8 genera, 15 of which were in genus Tintinnopsis. The most dominant species were Tintinnopsis baltica, Tintinnopsis beroidea and Tintinnidium primitivum in the spring. The most dominant species were Tintinnopsis tocantinensis, Tintinnidium primitivum and Tintinnopsis amoyensis in the summer. The most dominant specie was Tintinnidium primitivum in the autumn. The lorica oral diameter of the tintinnid community was larger in the summer [(35.9±8.2) μm] and autumn [(34.8±5.2) μm] than in the spring [(31.5±2.5) μm]. The Shannon index and Pielou index of the tintinnid community were both higher in the summer than in the spring and autumn. Our study may provide basic data for the future research on both the planktonic ecosystem and the development of the fishery industry.