【作者】 刘倩辉；

【导师】 胡文容；

【作者基本信息】 山东大学 ， 环境工程， 2010， 硕士

【摘要】 浮游藻类的种群结构与其生活水域的水质状况密切相关,是评价水体质量的一项重要生物指标。南四湖是南水北调东线工程的调蓄湖泊和输水线路的重要组成部分,研究湖内水体浮游藻类种群构成特征及分布规律,可为评估水体质量,预防控制湖泊富营养化,保障调水水质安全提供科学依据。本文对南四湖水体浮游藻类种群构成特征及水体营养状态进行了调查研究。本文主要研究内容如下：2008年6月～2009年5月在南四湖设置5个监测点,每月采样一次,对浮游藻类种群构成特征及季节变化进行了为期一年的调查研究。南四湖共检出浮游藻类8门59属117种；其中绿藻种类最多,共57种,占浮游藻类总种数的48.7%；硅藻次之,共28种,占浮游藻类总种数的23.9%；浮游藻类种数夏秋季节多,冬春季节少。各监测点浮游藻类密度和叶绿素口浓度变化范围分别为5×104～5500×104 cells／L、2.14-158.36mg／m3,浮游藻类密度季节变化表现为夏季>秋季>春季>冬季。浮游藻类优势种的优势度指数不高,变化范围为0.04～0.35,优势种种数较多,包括小球藻(Chlorella vulgar is)、二形栅藻(Scenedesmus dimorphus)、颗粒直链藻(Aulacoseira granulata)等23种。南四湖浮游藻类多样性指数和均匀度指数变化范围分别为1.56～2.36、0.59～0.84；多样性和均匀度较好,表明南四湖水体中浮游藻类群落结构较复杂,且群落种类组成的稳定程度和数量分布均匀程度较高。南四湖水体检出蓝藻10属19种,占藻类总种数的16.2%；各监测点蓝藻细胞密度变化范围为0-1120×104 cells／L,月均值为92.9×104cells／L；蓝藻种数及密度夏秋季节高,冬春季节低；蓝藻种群中的优势种是平裂藻属的种类,水华常见藻类如微囊藻属和鱼腥藻属的种类等占比例小或未检出。浮游藻类优势种不是易引发水华的蓝藻种类,气象气候、水流流态等环境条件不利于水华的形成,是南四湖未发生明显水华的重要原因。采用修正的卡森营养状态指数法(TSIM)、《地表水资源质量评价技术规程》(SL395-2007)规定的指数法、生物指标评价法评价了南四湖水体营养状态,评价结果为富营养。南四湖检出的浮游藻类多为淡水湖泊水体常见种类,部分种类为富营养化指示藻类。南水北调东线工程的实施,促进了南四湖汇水区的环境保护,湖水水质明显提高。为预防发生蓝藻水华,保障湖体水质达到调水水质要求,还应进一步采取建设人工湿地、中水回用、面源污染治理等水质改善措施,同时加强水环境质量监控预警体系建设。更多还原

【Abstract】 Phytoplankton community is closely related to the water quality and thus to be an important biological indicator for water quality assessment. Nansi Lake has been employed in the east route of the South-to-North Water Diversion Project for accommodating water storage and part of the water channel. Investigations of phytoplankton community are an important aspect in studying water quality, preventing and controlling eutrophication of lakes, and ensuring diversion water quality. This paper focused on the phytoplankton community characteristics and the assessment of water trophic status in Nansi Lake. The main researches included as follows:The composition characteristics and seasonal variations of phytoplankton in Nansi Lake were studied from June 2008 to May 2009.8 phyla,59 genera and 117 species have been identified from 5 monitoring stations based on a monthly sampling. The dominated Chlorophyta has 57 species, accounting for 48.7% of the total phytoplankton species, and Bacillariophyta has 28 species, accounting for 23.9% of the total phytoplankton speices. There were much more species in summer and autumn than that in winter and spring. The phytoplankton densities and chlorophyll a concentrations of each sampling station ranged from 5×104 to 5500×104 cells/L, and 2.14 to 158.36mg/m3, respectively. The quantity of phytoplankton in the order from large to small was:summer>autumn>spring>winter. The predominant indices were not high, ranging from 0.04 to 0.35, and there were 23 predominant species including Chlorella vulgaris, Scenedesmus dimorphus, Aulacoseira granulate, etc. The phytoplankton diversity and evenness indices varied from 1.56 to 2.36, and 0.59 to 0.84, respectively. It can be concluded that the phytoplankton community structure in Nansi Lake was complex, and the stability of the phytoplankton community composition and quantitative distribution showed a high degree in Nansi Lake.The species composition of cyanobacteria community revealed 10 genera,19 species, which accounted for 16.2% of the total number of phytoplankton species observed in Nansi Lake. The cyanobacteria densities of each monitoring station ranged from 0 to 1120×104 cells/L, with an average of 92.9×104 cells/L. The cyanobacteria species number and cell densities had the same variation trends during the year, with higher values in summer and autumn and lower values in spring and winter. The dominant species of cyanobaceria community were the species of Merismopedia, not the bloom-forming algae such as Microcystis, Anabaena, etc. The dominant species of phytoplankton community were not the species of cyanobacteria causing water bloom, and environmental conditions such as climate, hydrology were not suitable for the excessive propagation of cyanobacteria, which are the important reasons for that the water bloom has never occurred in Nansi Lake.The trophic state of Nansi Lake was investigated using the methods of modified trophic state index (TSIM), index defined by the "Evaluation of surface water quality technical specification (SL395-2007)" and biological indicators. According to the majority of the investigated parameters and indices derived from water quality and phytoplankton, Nansi Lake was eutrophic. Most of the detected phytoplankton speices were common genus in freshwater lakes and some species indicated eutrophication.The construction of the east route of South-to-North Water Diversion Project promoted the environmental protection in Nansi Lake watershed and the lake water quality has been meliorated significantly. To prevent water bloom occurring in Nansi Lake and achieve the required water quality for water diversion, it is still need to improve water environmental monitoring, control, emergency system and implement the water pollution control measures such as constructing the wetlands system, wastewater reuse, non point source pollution control, etc.更多还原