胶州湾特殊超微型浮游植物的分离鉴定及分布研究

Marine ultraphytoplankton refers to the photoautotrophic plankton smaller than 5 μm in diameter. In the course of a routine monitoring of ultraphytoplankton in the Jiaozhou Bay, a peculiar and unknown group (2-4μm in size with phycoerythrin and chlorophyll fluorescences) was observed with maximum abundance larger than 10000 cells/ml. It is difficult to identify these species due to their size, shape and morphological characteristics we already have. Their distribution patterns and influencing factors are still unknown. In this project, flow cytometry, microscopy (Epifluorescence microscopy, scanning and transmission electron microscopy), High Performance Liquid Chromatography, combined with molecular biology will be introduced for further identification. Spatial and temporal distributions of these unknown ultraphytoplankton will be investigated in the Jiaozhou Bay and its possible influencing factors will be analysed at the same time. It is important to determine why they occur in the Jiaozhou Bay and their potential influence on the ecosystem of the Jiaozhou Bay. Besides, in the Bay of Marseille and Gulf of Gabes (Eastern Mediterranean Basin), similar ultraphytoplankon was aslo observed. It is necessary to identify them and compare their similarities and differences in these bays. The present project will conduct a joint identification of the unknown species in the Bays of Jiaozhou and Marseille.

海洋超微型浮游植物指细胞粒径小于5μm的光能自养型浮游生物。我们对胶州湾超微型浮游植物分布进行常规监测的过程中，发现了一类细胞粒径为2-4μm、含有叶绿素和藻红蛋白荧光、最高丰度达10000 cells/ml的未知类群，已有结果显示它们并非单一物种组成。该类群细胞表面结构比较特殊，然而仅靠形态学无法对其进行种属鉴定，其时空变化与影响因子仍是未知。我们将流式细胞仪、显微镜、高效液相色谱与分子生物学等技术相结合，对该特殊类群进行形态结构、色素组成和种属组成的鉴定。同时分析特殊类群在胶州湾的时空变化特征，并结合环境因子探讨其在胶州湾出现的原因和条件。此外，地中海马赛湾（法国）和加贝斯湾（突尼斯）也有类似特殊类群出现，我们拟对不同海湾的相似类群进行种属鉴定，分析比较其异同，并进一步探讨它们分布的广泛性和物种的差异性。

海洋超微型浮游植物指细胞粒径小于5 µm的光能自养型浮游生物。我们对胶州湾超微型浮游植物常规检测过程中，发现了一类细胞粒径在2-4 µm、含有叶绿素和藻红蛋白荧光、丰度在102-104 cells/ml的未知类群。本研究将流式细胞仪分选、扫描电镜观察、高效液相色谱分析及18S rDNA基因序列分析相结合，对其进行种属组成鉴定。扫描电镜和高效液相色谱分析结果表明它们主要由青绿藻和隐藻组成，18S rDNA基因序列结果进一步表明它们主要是由微小单胞藻和隐藻属组成。本项目还分析了胶州湾该特殊超微型浮游植物的时空变化特征，其分布情况与常见超微型浮游植物聚球藻、微微型真核浮游植物和超微型真核浮游植物分布规律完全不同。结合环境因子和生物因子分析发现，温度是影响其分布的主要因素。马赛湾作为开放型海湾，与半封闭海湾胶州湾的环境存在明显差异。对马赛湾特殊超微型浮游植物丰度的季节变化分析发现，其分布规律与胶州湾差异显著。结合环境因子和生物因子进行分析发现，温度也是影响其分布的重要因素。此外，除了胶州湾和马赛湾，在桑沟湾、獐子岛、东海陆架等海域也发现了特殊超微型浮游植物的存在，但它们的分布规律和影响因素并不相同，体现出明显的地域差异性和分布广泛性。