【作者】 游江涛；

【导师】 韩博平；

【作者基本信息】 暨南大学 ， 水生生物学， 2006， 博士

【摘要】 浮游植物是水体颗粒物中最重要的组成，脂肪酸是其细胞组成的基本构件，且具有特殊的生理功能，是生态系统中物质和能量传递的重要物质基础。水体富营养化过程中浮游植物的组成也随之变化，因此研究不同水库和湖泊的富营养化程度与水体颗粒物中脂肪酸分布的关系有利于深入了解富营养化对生态系统的影响，也有利于掌握不同类型水华的发生机制。 本研究主要在2004年调查广东省不同营养状态的6座水库和2个湖泊，每2月采样1次。这些水体依据营养水平可以分为4类水体：贫营养水平的新丰江水库和流溪河水库、中富营养水平的飞来峡水库和深圳水库、富营养水平的汤溪水库和契爷石水库、富营养化的浅水湖泊(中心湖和仙女湖)。另外2005年还调查了黄龙带水库一次甲藻水华期间的动态变化。调查的内容包括营养盐等主要水质指标，浮游植物群落结构和生物量，颗粒物脂肪酸组成等。根据调查和测定的数据，本文分析了不同营养状态水体的颗粒物脂肪酸组成的特征，探讨了浮游植物群落在颗粒物脂肪酸组成中的作用。 贫营养水平的新丰江水库浮游植物以蓝藻、绿藻和硅藻为主。其2月和10月的浮游植物组成分布较均匀，而且2月和10月富含多不饱和脂肪酸的分歧锥囊藻的数量也明显高于4月和6月的。因此，新丰江水库在2月和10月的脂肪酸种类数很高，浓度也相对较高，脂肪酸多样性高。富含C16：1和EPA的硅藻是流溪河水库主要的浮游植物，但其颗粒物脂肪酸组成主要由饱和脂肪酸组成，EPA和DHA等多不饱和脂肪酸只出现在10月份，浓度很低。因此淡水硅藻的EPA含量可以有很大的不同。流溪河水库EPA含量低的小环藻不是营养价值高的食物。 中富营养水平的飞来峡水库浮游植物细胞密度较小，没有明显的优势种。各门藻类在4月和6月分布较均匀，但在12月总细胞数较高，富含饱和脂肪酸的蓝藻占绝对优势。飞来峡水库12月的总脂肪酸浓度最高，其多不饱和脂肪酸主要有C18：2、C18：3和DHA。深圳水库则以绿藻，蓝藻和隐藻等为主。深圳水库4月的脂肪酸种类数很多，脂肪酸多样性很高。可检测到的多不饱和脂肪酸有C18：3、C20：2、C20：3、C20：4、EPA和DHA等，其它月份没有检测到多不饱和脂肪酸。更多还原

【Abstract】 Phytoplankton is the most important component in seston (fine particles in water). Fatty acid, having important physiological function, is an essential biochemical component in the phytoplankton cells. It plays a central role in regulating trophic transfer of energy and biomass within the food web of aquatic ecosystem. As the composition and structure of a phytoplankton community varies over eutrophication, the relationship between trophic states and composition of fatty acids in seston could be useful for understanding of the processes of eutrophication, the effect of eutrophication on ecosystem function and the mechanism of algal blooms.In this research, six reservoirs and two lakes with different trophic status in Guangdong Province were investigated every two months in 2004. According to trophic states, these water bodies were divided into four groups: oligotrophicreservoirs-Xinfengjiang Reservoir and Liuxihe Reservoir, meso-trophic reservoirs-Feilaixia Reservoir and Shenzhen Reservoir, eutrotrophic reservoirs -TangxiReservoir and Qiyeshi Reservoir, and eutrophic shallow Lakes-Zhongxin Lakeand Xiannv Lake (the two sublakes of Xing Lake). In addition, a dinoflagellate bloom was investigated in 2005, in which the water quality variables such as phosphorus concentration and nitrogen concentration, phytoplankton community structure, particle organic carbon and fatty acid composition of phytoplankton were measured. The study focuses on the possible relation between phytoplankton community structure and fatty acid composition over eutrophication processes.In the oligotrophic reservoirs, Cyanophyta, Chlorophyta and Bacillariophyta were dominant in Xinfengjiang Reservoir. The relative abundance of Cyanophyta, Chlorophyta and Bacillariophyta was average in February and October. The abundance of Dinobryon divergens that is rich in polyunsaturated fatty acid was obviously higher in February and October than that in April and June. Thus, the concentration and diversity of fatty acids were high in Xinfengjiang Reservoir in February and October. Bacillariophyta, which is rich in C16:l and EPA, was the main group of phytoplankton in Liuxihe Reservoir. But saturated fatty acid is the main更多还原