| Landscape water system of Shanghai Ocean University new campus (SHOUWS) was completed in 2007, located in the planning area of Lingang new district of Shanghai, by east of Dishuihu Lake and south of Donghai Bridge, the water surface acreage was 92 Mu, and salinity was 1.8~3.2, it was found many fish species, such as Mugil cephalus, Anguilla japonica and Coilia nasus, so it's a minitype estuarine landscape water. For shorting of essential ecosystem factors and being polluted by domestic sewage from the process of the construction of the campus, the water quality was once worsen . Ecological construction was carried in SHOUWS in 2008, the construction technology including: vegetation buffer zone building, artificial wetland structure, water circulated, aquatic plant community structure, aquatic animal stocking, etc. This study on SHOUWS after the ecological construction project, according to consecutive monitoring data collected from 2009 to 2010, analyzed the physical and chemical factors, the phytoplankton community structure, advanced aquatic plant extant weight, N, P incoming and outgoing of water. Besidely, the effects of this project was evaluated by various methods, aiming to provide reliable reference data for long-term effective treatment and theoretical support.1. The community structure of the phytoplankton after ecological construction of SHOUWS.122 phytoplankton species were detected during the experiment process, belonging to 6 categories and 57 genera. The amounts of chlorophyta were the major, then the Bacillariophyta and Cyanophyta; The average density of the phytoplankton in SHOUWS were 1.22×10~7 cells/L, far above the density of Luchaoyinhe River (3.81×10~7 cells/L ), cyanphyta, both of these two water, were the highest and the species around 92.9% and 43.7%. The density of phytoplankton in spring was the highest, arriving the peak in May, and began to decline from June gradually, then kept at a stable lower level. the average density of the phytoplankton showed a higher level in East Lake and West Lake of SHOUWS. Change of the Chlorophyll a concentration appeared the same trend with the change of the phytoplankton density and it declined to maintain a low level gradually along the implementation of ecological construction measures, being a lower level in July, 2009 and the correlation coefficient with phytoplankton density was 0.76. The dominant species of Phytoplankton in SHOUWS were all of the Cyanophyta, mainly including Phorimidium tenus, Synechococcus lividus; Shannon-Weaner Diversity index and Mergalef index showed rising trend Monthly, average value were 2.768 and 2.847, belonging to Mild - moderate pollution state.2. Variation of the water quality after ecological construction The water quality of SHOUWS was improved obviously after ecological construction, according to the data of the physical and chemical parameter. The total average concentration of TN was 1.5mg/L, consisting to the levelⅣof the surface water from June, 2009 to October, 2010. In second half of 2010, TN was up to levelⅢ. As the result of the concentrations of the NH3, NO2-, NO3-, SRP, CODMn and Chla were much lower than Luchaoyinhe River and Shanghai Maritime University water system (SHMUWS). The average transparency was 80cm, higher than Luchaoyinhe River 30cm and higher than SHMUWS 35cm. The concentration of the TN in St2 was the highest, Chla and CODMn in St3 showed a high level, NH3 in St4 was higher, NH3, Chla and CODMn in St5 were higher, the water quality of St6 and St7 were the best, Iwq was 3.7 (Ⅲlevel) from July.2009 to October. 2010 that was lower than January to June of 2009. Meanwhile, the Iwq in both SHMUWS and Luchaoyinhe River were low, but little difference among every sites.3. Status of incoming and outgoing of the N, P, and aquatic plants community composition in SHOUWS after the ecological construction project. A submerged plant community initially formed by Vallisneria spiralis L., Hydilla verticillata Royle, Ceratophyllum demersum L., basically instead of the dominance of the Myiopphyllum spicatum L. after the ecological construction. West irrigation river, West Lake and East Lake were the main distribution area of aquatic plants. Among the emergent plants,Thalia doalbata, Pontederia cordata had the widest distribution, the highest biomass and grew best. According to the research of the budgets of nitrogen and phosphorus of SHOUWS in 2010, the import of nitrogen and phosphorus of the rainfall were 920kg and 91.3kg in whole year, The export of the nitrogen and phosphorus fixed by silver carp and bighead carp were the highest(768.3kg, 68.5kg) and the second is the reaping of the emergent plants (379kg, 33.8kg) , consequently the P showed a balance of payments basically, and N content overflow 125kg.By the ecological construction, the density of the phytoplankton declined significantly in SHOUWS, and water quality improved obviously, the distribution of the advanced aquatic plants increased, the diversity of submerged plant increased, and the superior species occupied dominant status. Hence, a landscape pattern of different spatial scales was formed and it played an important role on the beatification of the SHOUWS. According to the investigation, a long-term management is needed in SHOUWS and includes: 1. optimizing the structure of aquatic plants and ensuring its growth and reproduction; 2. optimizing the structure of the aquatic animals, including fish, large crustaceans; 3.periodic harvesting aquatic plants, reducing the nutrient load of the water; 4. cleaning the garbage of SHOUWS, beautifing the environment; 5. periodic environmental monitoring, establishing a steady-state ecosystem models in SHOUWS. |
PDF Full Text Request