杭州西湖轮虫的群落结构及与水体环境因子的关系

摘要

2007年1月-2010年10月,对杭州西湖进行调查研究,利用综合营养状态指数对西湖的营养状况进行评价,通过种类组成、优势种、多样性指数等指标探讨西湖轮虫的群落结构与水体营养状况之间的关系.结果表明,西湖总体处于中-富营养状态.调查期间共检出轮虫29种,以角突臂尾轮虫(Brachionus angularis)、螺形龟甲轮虫(Keratella cochlearis)等最为常见；总数量处于较低的水平,多样性水平不高；各采样点在不同年份表现出不同的季节变化规律.相关性分析结果表明,西湖轮虫密度与水温、TLI指数、总氮、高锰酸盐指数、透明度和pH值的相关性高度显著；Margalef多样性指数和Shannon-Wiener多样性指数与水体环境因子表现出不同的相关性.研究发现,西湖轮虫结构不仅与水体的营养状况关系密切,还受引水过程引起的水动力学的影响,从引水入湖口到出水口存在一个以水动力学过程为主导的生态梯度.%In the present study we evaluated the trophic status of West Lake on basis of investigations from January of 2007 to October of 2010. According to the data associated with species composition, dominant species, density and diversity of rotifers, the relationships between rotifer community structure and eutrophication were evaluated. The result indicated that the water in West Lake had been in a stale of eutrophication. The dominant rotifer species were Brachionus angularis and Keratella cochlearis in all 29 species. The amount and diversity of rotifer species are all low. Structures of rotifer community were different in seasons, years and locations. The correlation analysis showed that rotifer density was significantly correlated with water temperature, status of eutrophication, total nitrogen, SD, CODMn and pH, respectively. There were significant correlations between Shannon-Wiener diversity index and environmental factors, but only total-nitrogen had obvious correlation with Margalef diversity index. The study showed that there existed an ecological gradient of the community structure of rotifers between intake and outlet, which were influenced by hydrodynamics of water diversion system.