The Effect Of Storing Water In Three Gorges On Algae In The Exit Of Jialing River In Spring

Jialing River is an important tributary of Three Gorges reservoir,the water quality of which in Chongqing city effects drinking water safety and water environment change. In recent years, the progress of eutrophication in the exit of Jialing River was faster and faster,and the algae was active. In order to recognize the effection on algae'activities in Jialing River during storing water to 175 meter (elevation) in Three Gorges,the investigation in spring had been studied. Compared with the dates in 2007, the study analyzed algae changes in spring in 2009 through field sampling, physiochemical determination, identification of algae,date analysis,et al, so as to provide a scientific basis for algae control during storing water to 175 meter (elevation) in Three Gorges.The research results:From 1 to 3 months in 2007, the water level was 159.46~161.64m, velocity was 0.037~0.168m·s-1, air temperature was 7.4~14.9℃, water temperature was 9.3~14.1℃, NO3- was 0.87~3.35mg·L-1, PO43- was 0.162~0.219mg·L-1, turbidity was 28.4~45.8NTU, transparency was 0.7~1.1m;From 1 to 3 months in 2009, the water level was 163.28~169.48m, velocity was 0.015~0.124m·s-1, air temperature was 4.6~12.8℃,water temperature was 8.8~12.8℃,NO3- was 0.92~1.57mg·L-1,PO43- was 0.017~0.089mg·L-1, turbidity was 3.5~13.0NTU, transparency was 1.5~3.0m;During first storing water to 175 meter (elevation) in Three Gorges,the water level of Jialing River increased,the velocity became slow,the water capacity of Jialing River increased,the nutrient of samples decreased, the transparency of the exit of Jialing River increased,the turbidity decreased,and storing water effected no obvious.From 1 to 3 months in 2007,7 phyla, 51 genera and 124 species of algae were identified in the exit of Jialing River, Bacillariophyta were 22 genera and 78 species of algae,Chlorophyta were 18 genera and 29 species of algae,Cyanophyta were 6 genera and 9 species of algae,Cryptophyta were 2 genera and 4 species of algae,Pyrrophyta were 1 genera and 2 species of algae,Euglenophyta was 1 genera and 1 species of algae, Chrysophyta was 1 genera and 1 species of algae;From 1 to 3 months in 2009,7 phyla,70 genera and 168 species of algae were identified in the exit of Jialing River, Bacillariophyta were 27 genera and 91 species of algae,Chlorophyta were 27 genera and 47 species of algae, Cyanophyta were 8 genera and 14 species of algae, Cryptophyta were 3 genera and 8 species of algae,Pyrrophyta were 2 genera and 4 species of algae,Euglenophyta were 2 genera and 3 species of algae,Chrysophyta was 1 genera and 1 species of algae.The species of algae in 2009 increased 35.48%,and the species of Bacillariophyta increased 16.67%,the species of Chlorophyta increased 62.07%,the species of Cyanophyta increased 55.56%;the species ratios of Bacillariophyta,Chlorophyta and Cyanophyta were 1:3.20:8.62 in 2007 and 1:3.37:6.53 in 2009.During first storing water to 175 meter (elevation) in Three Gorges,the composition of algae had changed.From 1 to 3 months in 2007,Algal density was 12.00~120.93×104·L-1,the dominant algae were 9 species (Bacillariophyta were 6 species: Cyclotella asterocostata, Stephanodiscus minutulus, Melosira granulate, Melosira granulata var.angustissima, Melosira varians, Synedra acus; Cryptophyta was1 specie: Chroomonas acuta; Cyanophyta was 1 specie:Anabaena variabilis; Pyrrophyta was 1 specie: Peridinium bipes); From 1 to 3 months in 2009, Algal density was 2.07~73.76×104·L-1, the dominant algae were 15 species (Bacillariophyta were 8 species: Cyclotella asterocostata, Stephanodiscus minutulus, Melosira granulate, Melosira granulata var.angustissima, Melosira varians, Fragilaria vaucheriae, Fragilaria construens var.venter, Diatoma vulgare; Cryptophyta were 3 species: Chroomonas caudate, Chroomonas acuta; Cryptomonas erosa; Cyanophyta were 2 species: Oscillatoria chlorine, Phormidium acutissimum; Pyrrophyta was 1 specie: Peridiniopsis elpatiewskyi). During first storing water to 175 meter (elevation) in Three Gorges,algal density in the exit of Jialing River decreased, the species of dominant algae decreased.Because the velocity became slow during 2009.1~2009.3, the dominant algae of diatom were not suitable for growth.The species of non-dominant algae increased,the algal diversity index of Shannon-Wiener increased during algal active period.Through identification of algal bloom species in exit of Jialing River,which is Cyclotella asterocostata.