浙江青山水库浮游植物群落结构变化及与环境因子的关系

于2009年按季度对浙江省临安市内的青山水库进行调查,测定了水体环境因子、浮游植物群落,采用营养状态指数法对水库水质现状进行了分析和评价,并探讨了浮游植物与环境因子之间的关系。结果表明:青山水库处于轻度富营养化和中度富营养化之间,水库入库处营养状态综合指数高于库中和大坝处。调查期间共发现浮游植物7门40属89种。不同季节浮游植物主要优势种类不同,春季以硅藻、隐藻和甲藻为主,夏季以蓝藻和绿藻为主,秋季以蓝藻、硅藻和隐藻为主,冬季以硅藻和隐藻为主。相关分析表明,青山水库浮游植物密度与出入库流量和透明度呈显著负相关,与总磷呈显著正相关。典范对应分析(CCA)表明,出入库流量、水温、溶解氧和营养盐是影响水体浮游植物分布格局的重要环境因子。

PHYTOPLANKTON COMMUNITY VARIATION AND RELATIONSHIP WITH ENVIROMENTAL FACTORS IN QINGSHANHU RESERVOIR,ZHEJIANG PROVINCE

Qingshan Reservoir is an important utilization large reservoir which was built in 1964.Its eco-environment and water management have a great significance on sustainable development of this area.With the fast economical development,the water quality has been declined as an amount of pollutants discharged.To explore the characteristics of the phytoplankton community structure and the response of water quality,a survey was carried out quarterly in Qingshan Reservoir in 2009.Based on the analysis of phytoplankton and water samples from inflow,center and dam in Qingshan Reservoir,the characteristics of community structure and abundance distribution were studied,and the water situation was evaluated.Cell number and species identification were performed by light microscope.The dominant population,species diversity and community structure of phytoplankton were determined as well.A total of 89 species in 40 genera and 7 divisions were identified,which the most abundant group was Chlorophyta,with 33 species that account for 37％ of total species,followed by Bacillariophyta (27 species),Cyanophyta (17 species),Euglenophyta (6 species),other alges (6 species).The abundance of phytoplankton cells varied from 6.20 × 105 to 1.18× 107 cells/L (averaging 4.88 × 107 cells/L).The main physical and chemical indicators results showed that the water quality of Qingshan Reservoir was in the lightmiddle eutrophic state.The trophic state index was higher in inflow than in center and dam sites.The concentrations of total nitrogen and total phosphorus were higher than the surface water quality standards Ⅳ value.The indices of Shannon-Wiener,Margalef and Pielou Evenness were 1.37-2.23 (averaging 1.79),0.56-1.52 (averaging 1.05) and 0.45-0.77 (averaging 0.64),respectively.The dominant species of each month were identified and their contribution to the total abundance was analyzed.The seasonal variation of phytoplankton community structure was significant.In spring Bacillariophyta,Cryptophyta and Pyrrophyta dominated,in summer Cyanophyta and Chlorophyta dominated,in autumn Cyanophyta,Bacillariophyta and Cryptophyta,and in winter Bacillariophyta and Cryptophyta.The relationship between phytoplankton and environmental factors were discussed.Correlation analysis showed that there was significant negative correlation between phytoplankton density and transparency,inflow,outflow,and significant positive correlation between phytoplankton density and TP.Canonical correspondence analysis (CCA) showed that the inflow,outflow,water temperature,dissolved oxygen and nutrients were important environmental factors affecting the distribution pattern of phytoplankton.Qingshan Reservoir is located in a typical subtropical monsoon climate area,seasonal changes in the density of phytoplankton communities significantly affected by seasonal changes in watershed hydrology,and in particular,rainfall,temperature and hydraulic retention time are the main factors affecting phytoplankton community.