| Water is the source of life and it is one of the necessary ecological factors for all kinds of life.The quality of water resources directly affects people’s quality of life.The research selected eight representative cross sections of the Hunhe River for three surveys of water samples in May,July,and October,namely spring,summer,and autumn.The algae in each section were observed,identified and counted,and the water quality was evaluated by diversity index.The typical cross-section water samples in the Hunhe River Basin was taken,and nitrogen and phosphorus were added in the water samples to cultivated indoor.The species composition,abundance and dominant species of algae were analyzed,and the effects of different concentrations of nitrogen and phosphorus on the dynamics of algae were discussed.The ecological health evaluation of the Hunhe River basin was conducted by using three levels of physical,chemical,and biological evaluation systems,providing a reference for a thorough understanding of the ecological status and protection strategies of the Hunhe River basin from a macro perspective.The research found that there were 7 phytoplanktons,69 genera and 124 species(including variants)in the Hunhe River Basin.There were 52 species of green algae,41 species of diatoms,15 species of Cyanophyta,5 species of Cryptophyta and Bare Algae,4 species of Chrysophyta,and 2 species of Dinophyta.The abundance of algae is expressed as autumn more than summer than spring.In Hunhe River,there were 24 common species and 9 dominant species.According to the analysis of diversity index,Hunhe River was medium pollutied.The addition of nitrogen and phosphorus nutrients to the interior of the Hunhe River water samples showed that the algae composition and quantity in the experimental groups were significantly different from those in the Hunhe River.There were 4 divisions of algae in the natural water body before cultivation,9 genera and 21 species.After indoor cultivation,a total of 61 species of planktonic algae belonged to 6 divisions,42 genera,61 species were identified.When adding P was 0.2 mg/L.The average abundance of phytoplankton was the highest,which was 1.94×107 ind/L.When adding N was 25 mg/L and P was 1 mg/L,the planktonic algae were abundant.Algae have the lowest abundance with an average of 1.11×106 ind/L.There were 25 common species in indoor cultivation and 9 dominant species.The P concentration was 0.4mg/L,Microcystis was the absolute dominant species.The ecological health assessment showed that the Changqing Bridge section which located in Shenyang was onlg healthy section,while the worst section was Shenfu Irrigation Ditch which located in Fushum.The other six sections were all in sub-healthy situation.In summary,the algae composition of the Hunhe River showed seasonal dynamics,and algae diversity indexes showed that the water quality of studied sections of the Hunhe River were light or medium polluted.By adding nutrient salts to the water samples,it was found that phosphorus was more important than nitrogen to affect the growth of algae.Therefore,the input of phosphorus should be strictly controlled in river protection.The macro-eco-health evaluation showed that most sections of Hunhe River were in a sub-healthy state,but the cross-sectional health status in Shenyang area was better than that of in Fushun area.It was recommended that the overall ecological construction and protection of the coastal area along the Hunhe River should be further strengthened. |
