Study On The Correlation Of Lake Water Environment And Algae In The Core Area Of Jiuzhaigou

Jinzhaigou nature reserve is transition between Qinghai-Tibet Plateau and the Sichuan ecologo interlocks,locating the eastern edge of the Qinghai-Tibet Plateau, which includes 118 mountain lakes, linking with spring,fall and sands, the pick of which is water. The water is Jiuzhaigou's soul, so it is the basis of sustainable tourism development of iuzhaigou to protect water resources and the ecological environment in this place. Reserch depends on "Jinzhaigou and Huangiong" project of water reasoures protection startup by Sichuan scientific and technological department.In this paper, the correlation between the water environment and algae species was carried on from May 2005 to January 2006, which were in the core of Jiuzhaigou Colorful lake and Pearl waterfront, which could provided scientific basis and foundation of information for the protection of the ecological environment lakes of Jiuzhaigou. The results showed:1,The physical and chemical factors of Colorful lake and Pearl waterfrontThe average total nitrogen was 2.436 mg/L,2.404mg/Lrespectively and the average of P was 0.039 mg/L,0.041 mg/L respectively and N/P was 62.46 : 1, 58.63 : 1 respectively, which proved that P was the limiting factor of algae's growth in Colorful lake and Pearl waterfront.The COD_Mn of Colorful lake was 0.82～1.48 mgO₂/L, BOD5 was 0.65～1.30 mgO₂/L; the COD_Mn of Pearl waterfront was 0.72～0.83 mgO₂/L, BOD₅ was 0.35～0.51 mgO₂/L, which proved the quality of water pertained to theâ… and the content of dissolved oxygen was high and the content of organic substances was low in Colorful lake and Pearl waterfront.The temperature of Colorful lake was 8.8～16.1℃. The average temperature of A1～A6 was 10.71℃,12.67℃,12.13℃,10.35℃,10.73℃,11.28℃respectively. The temperature of Pearl waterfront was 8.80～12.30℃. The average temperature of B1～B5 was 10.35℃,10.41℃, 10.56℃, 9.69℃, 10.18℃respectively. The PH of them was higher than 7. The total hardness of Colorful lake was 184.2～211.2 mg/L and average was 192.3 mg/L; the total hardness of Pearl waterfront was 190.8～193.4 mg/L and average was 192.1 mg/L.2,Studying the rule of algae's changesPhytoplankton were identified 5, 74 genera, 183 types of species (including varieties) in Colorful lake and Pearl waterfront. In aspect of species composition, Bacillariophyta had 110 species accounting for 60.11%;Chlorophyta had 41 species accounting for 22.40%; Cyanophyta had 25 species accounting for 13.66%.The types of Phytoplankton were Bacillariophyta—Chlorophyta—Cyanophyta. The temperature in Colorful lake and Pearl waterfront was 8～15℃which was suitable for Bacillariophyta's growth,which was the dominant species from the sampling point.COD_Mn and BOD5 of A2,A3 and A6 were significantly higher than those of other points and the content of organic matter was high along Colorful lake coastal zone-At the same time, because the temperature along with the coastal zone was higher, the the cell density of phytoplankton, Chl-a and biomass were higher obviously than the heart of lake.The sampling points of Pearl waterfront was in the same section, so whose differences were not significant, where the biomass of Filamentous Green Algae was linear growth model monthly.Analysing the relativity among Chl-a, cell density,biomass of phytoplankton and environmental factors, water temperature and TP had obvious effects on the biomass of phytoplankton in Colorful lake and Pearl waterfront.Based on the stepwise regression analysis of environmental factors, the environmental factors affecting angle's growth were little different between Colorful lake and Pearl waterfront. Every body of water with three or four environmental factors were selected, in which water temperatures had shown a positive correlation; through principal component analysis, water temperature had advantage of phytoplankton which provided theoretical basis for indoor simulated experiments. 3,Studying the rule of algae's growth with different temperature in JiuzhaigouAs the time extension, the dominant species, were replaced gradually by microBacillariophyta, which showed the rise of temperature might bring profound effects on the community composition of algae in Jiuzhaigou.The average of phytoplankton's biomass was the most, reaching 0.0115 mg/L, which was significantly higher than low-temperature 0.0035 mg/L.The average of Filamentous algae's biomass was 0.0074 g, 0.0125 g, 0.0288 g, 0.0387 g with 8℃, 11℃, 14℃. 17℃respectively, which showed that the phytoplankton's biomass and filamentous algae increased significantly with the rise of temperature.As the water temperature was natural factors, it was hard to control it. The influence of water temperature on phytoplankton through artificial simulation showed that the phytoplankton's biomass,cell density and filamentous algae's biomass had markedly increased with the rise of temperature. Moreover, with the global warming theory,it, strengthening the protection of the ecological environment, was need to do to adjust the scenic microclimate and alleviate the rise of water temperature. Besides it, improving the quotiety of vegetation coverage and reducing the importation of nutrient phosphorus, was to do to control the growth of phytoplankton.