Characteristics Of Algae Community In The Liujiaxia Reservoir And Water Quality Assessmen

Liujiaxia reservoir is located in the upper reaches of yellow river,by the Gansu linxia hui autonomous prefectures yongjing,dongxiang,linxia,ji shi shan four counties,reservoir storage capacity of 5.7 billion cubic metres,the waters of 130 square kilometers,with multi-function of electricity,flood control,irrigation,travel,shipping.By reason of the reservoirs of the ecological system of environmental condition volatile,fast and not law,biological diversity is relatively low and ecological niche is comparatively high.Differs from the lake,reservoir a significant feature at the reservoir is built out early in the process of water storage has flooded a number of vegetation.Degradation provide both food and special habitat and asylum.Reservoir algae grow on the main restrictions factor is light and nutritive salt.From the army to the dam,unit of the volume growth rate of algae shows decreasing,but growth rate of per unit area not by much.This research analysis confirmed 6 sampling sites in Liujiaxia reservoir,fromJul.2008 to Jun.2009,determined physical-chemical indexes such as water temperature,PH,total nitrogen,total phosphorus every mouth.Appraised phytoplankton species complexity ; numerated phytoplankton cell density ; analyzed various kinds of biologicaldiversities,and making ecological evaluation of water quality.The result demonstrated that:①Total nitrogen of Liujiaxia reservoir ranged 0.19～0.47mg/L,and total phosphorus ranged 0.036～0.09mg/L in one year.Using the software of SPSS 17.0 to analyse the relationship of the phytoplankton abundance,water temperature,PH,total nitrogen and total phosphorus.Educing the phytoplankton abundance,total nitrogen and total phosphorus have remarkable interrelated relationship;TN/TP range from 3 to 15,total nitrogen maybe the restrictive factor in Liujiaxia reservoir.Liujiaxia reservoir's water quality satisfy water standard ofⅡ.②9 phyla , 55 genera and 116 species(including varieties)of phytoplankton community in the waters of the Liujiaxia reservoir were identified.Bacillariophyta and Chlorophyta were dominating in most mouth of one year.Cyanophyta and Chrysophyta were increased largely in spring.With the rainy season's coming in summer,Chlorophyta is preponderant obviously.The species and quantity of Bacillariophyta get increase in autumn.In general,the phytoplankton of Liujiaxia reservoir represent the variation with years in different condition of hydrology and climate.③Analyzing the index of biologic diversity of phytoplankton,index of Margale,index of Shsannon-Wiener and index of Pilou all show that water quailty of Liujiaxia reservoir was between mild-contaminated and mid-contaminated.Moreover;overall evaluation of the phytoplankton showed that,Liujiaxia reservoir water body has been in the middle nutritional level.Water quality is best in summer and worse in spring.