Research On Phytoplankton Of The Main Enclosed Water In Hefei City

In recent years, the rapid development of economic and social construction of Hefei city had a significant impact on water environment of lakes and reservoirs in enclosed water. The study investigated the water quality of main enclosed water( the Round City River, Emerald Lake, Swan Lake,Dong Pu Reservoir,Da Fang Ying Reservoir) of Hefei city and study on the temporal-spatial variations of distribution of phytoplankton,and by the method of correlation-weighted trophic level index,the level of eutrophication was evaluated.According to the temporal-spatial variations of physical and chemical indicators(p H, CODCr, NH3-N, TN, TP and Do) of the Round City River, Emerald Lake, Swan Lake, Dong Pu Reservoir and Da Fang Ying Reservoir, it can be found that:(1) There was no significant difference in the temporal-spatial variations of p H and CODCr in the same bady of water.(2)The temporal characteristics of DO in the same bady of water was significant, but randomness and irregularity.(3) In addition to the Round City River, the temporal-spatial variations of NH3-N in the other water bodies was it’s content in January 2016 higher than in July and October 2015, it may be mainly due to the winter in january, the temperature is low, is not conducive to the volatilization of NH3-N, but there was no significant spatial variations of NH3-N content in the same bady of water.(4)In addition to the Round City River, there was no significant difference in the temporal variation characteristics of TP in the other water bodies.(5) The spatial variation of NH3-N, TN and TP of the Round City River was significant. Their content of 1~5 sampling points is smaller, started to rise sharply from the point 6, 6~9 sampling points greatly, and owing to it was observed that near the surface of the water had a strong urine smell, speculated that domestic sewage may be discharged to near the point and it connected the water of Xiao Yao Jin Park,which has been seriously contamintaed.According to the temporal-spatial variations of phytoplankton cell density, the chlorophyll content and species of the enclosed wate(the Round City River, Emerald Lake, Swan Lake,Dong Pu Reservoir,Da Fang Ying Reservoir),it can be obtained that:(1) The temporal characteristics of phytoplankton cell density, chlorophyll content and specie numbers were : October 2015﹥July 2015 and January 2016.(2) In addition to the Round City River, the temporal-spatial variations of phytoplankton cell density and chlorophyll content in the other water bodies was: the content between sampling points was different, but irregularity.(3) The temporal variation characteristics of chlorophyll and phytoplankton cell density of the Round City River was:phytoplankton cell density of 1~4 points is higher than 6~9.(4) The temporal variation characteristics of the phytoplankton species: there were the largest number of phytoplankton species in the Round City River, the second number of phytoplankton species in Dong Pu Reservoir and Da Fang Ying Reservoir, the minimum number of phytoplankton species in Swan Lake and Emerald Lake;The difference of phytoplankton specie numbers in the same bady was not significant.(5)The main composition categories of phytoplankton species were Chlorophyta, Bacillariophyta and Cyanophyta,respectively accounting for the total species 35.8%, 30.3%, 20.2%, and the rest of Dinoflagellate, Euglenophyta, Chrysophyta and Cryptophytaphyla are less, accounting for the total species 13.7%.By the method of correlation-weighted trophic level index,and selecting four parameters that total nitrogen, total phosphorus, chlorophyll content and chemical oxygen, respectively, the level-eutrophication of the Round City River, Emerald Lake, Swan Lake,Dong Pu Reservoir and Da Fang Ying Reservoir were evaluated. As a result, the level-eutrophication of the Round City River was the highest, severe eutrophication, Swan Lake and Emerald Lake were the second, ranged from moderate and severe eutrophication, Dong Pu Reservoir and Da Fang Ying Reservoir were the least,medium nutrition type.