Phytoplankto Diversity Analyse And Water Quality Evaluate Investigation Of Jingbo Lake

May,July and October of 2006 and January of 2007,Phytoplankton ecological investigation was conducted in 8 typical sampling sptos in Jingbo Lake.Qualitative and quantitative analysis were carried on for all sampling spots in laboratory.Phytoplankton communities and biodiversity were determined by multivariate statistic analysis.The correlation between phytoplankton and environment was determined by Pearson analysis. Referenced evidences for water resource management of Jingbo Lake were proposed.Total 8 phylas and 108 species were identified,among which,the majority were Clorphyta (47) and Cyanophta(29),following was Bacillaroiphyta(18) and others(14);Clorphyta was the dominant group in total phytoplankton.The total mean abundance and biomass were 4311.33×10~4 ind./L and 44.89mg/L.We discoverd 16 dominant species in four seasons.The seasonal variation influenced the dominant species' change.According to diversity index exponential ANOVA analysis of three phytoplankton kinds,diversity index differences in every season and every typical sampling spots were signicint(p＜0.01),which indicated that spacetime change was obvious.There were different ranges in different diversity index,Shannon-Wiener's index was from 0.96 to 4.53;Margalef's index was from 1.51 to 4.94;Pielou's index was from 0.27 to 0.83 respectively.Seasonal comparison of Shannon-Wiener's indexes were summer＞spring＞autumn＞winter,and Margelef's and Pielou's indexes were summer＞spring＞winter＞autumn.The multidimensional scaling(MDS) results showed that phytoplankton community compositon had siginicant differences among these sampling spots in each season; phytoplankton communities of each sampling spots in the group had highest comparabilities, but phytoplankton communities of each sampling spots among the groups had lowest comparabilities.Reults of Pearson analysis beween phytoplankton and environmental factors showed that phytoplankton abundance,biomass and environmental factors chosen in this investigation didn't have correlation.According to the phytoplankton compositon,biomass and diversity index,it was conducted that water quality in summer of Jingbo Lake was best,that in spring and autumn was worse,and that in winter was worst;upriver water quality was better than lower reaches of the river;water quality of the whole river was a poor-middle nutrition live type.Compared with results of phytoplankton survy ten years ago,phytoplankton varieties and numbers of this investigation decreased,which was 74 genera and 143 phylums in 1997 had reduced to 55 genera and 108 phylums now.About the diversity index was that Shanno- Wiener index in summer was higher than 1991,water quality became better;but Shanno- Wiener index in autumn was lower than 1991and water quality became worse.