| Water is one of the basic elements of urban landscape,and urban;is an important part of modern landscape design.Due to the inflow of various pollutants and the characteristics of the water body,the urban landscape water is highly eutrophic,which result in the facts that the water turns black,the smelly and the blooms happens frequently.The urban landscape water is not only losing its ornamental value and ecological functions,but also endangering the public health.Based on the theory of ecology,the combination of environmental science and landscape ecology is used to explain the main influencing factors of eutrophication and water bloom in urban landscape water,and provide scientific basis for urban landscape ecological design.A field experiment was carried out to investigate Chlorophyll a?Chl.a?Demagnesiumchlorophyll a.?Dechla.?,nutrient and physicochemical properties of samples collected from DongFeng river during algae bloom summer and winter,The results showed average of Chi.a was respective 29.76?g·L-1 and 23.72?g·L-1 in summer and winter,and Dechla.was 18.3?g/L and 19.32?g/L respectively.Further,Chl.a and Dechla.chang bigger in the different sites in winter than summer,which show spatial heterogeneity of phytoplankton in winter.Content of Dechla.was the highest 40.73?g L-1 in east 200 meters of Huayuan road bridge?I-2#?among all cross sections,whereas dissolved oxygen?DO?was the lowest 1.48 mg·L-1,therefore the most serious water pollution occur in the section.Average of Total Nitrogen?TN?and Total Phosphorus?TP?was 226.08 mg·L-1,6.25 mg·L-1 respectively during summer,TP varied from 4.88 to 8.41 ?g·g-1,average of TN and TP was 343.75 Mg·L-1,11.70 mg·L-1 respectively in winter,and variation of TP was from 6.29 to 20.60 mg·L-1 which varied widely in the different sites in winter,TP show spatial heterogeneity in winter.Therefore water quality maintained a high eutrophic level in summer and winter.Moreover the concentration of Chl.a had no obvious relation with NH3-N?TN?TP?TN/TP,whereas Chl.a was found to be positive correlated with pH and turbidity during"water bloom".In addition,the variation of Chl.a and Dechla.was 3.21?10.74 ?g·g-1 and 11.24?19.33?g·g-1 n sediment,their average was 6.82?g·g-1 and 13.81?g·g-1 respectively.Content of TN in sediment varied from 12.66 to 15.94 mg·g-1?average was 14.35 mg·g-1,Along the flow direction from Huayuan road to the DongMing road,tendency of TN was decreasing first and then increasing,minimum 12.66 mg·g-1 was in west JingShan road bridge?I-2'#?,whereas range of TP was from 5.40 to 8.77 mg·g-1,average was 6.56 mg·g-1,and tendency of TP reduce gradually from Upper to downstream river along the flow direction.In conclusion,algae recovery and nutrient release in sediment is one of the important factors affecting green algae bloom in the summer.Monitoring and analysis of water quality can integrate the water purification technology,urban landscape water design and artistic function improve the water ornamental value and ecological benefits.Furthermore,these methods could influence the current environmental characteristics of China's urban landscape water body construction,pollution prevention and control,transformation and management in a positive way. |
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