Study On The Characteristics Of Community Structure Of Periphytic Algae And Water Quality Assessment In The Deganba Riparian In Jiangjin Of The Upper Reaches Of Yangtze River

Riparian is an important channel of exchange between water and land areas of energy, materials and organisms. It has regulated rivers micro climate, protected biodiversity, protected surface water and groundwater resources and other functions, can play a decisive role in the aquatic and terrestrial ecosystems. Periphytic algae was grew in the riparian water-land at the junction of the first line ecotone. On the one hand, it has a high primary productivity, which provides food source for aquatic animals; On the other hand, its impact on the community structure and diversity by water temperature, nutrients and other environmental factors. Therefore, studies of periphytic algae species composition and variation, will assess the status of riparian environment and pollution prevention riparian provide basic data to provide a scientific basis for the protection of riparian structure and function.In this study, we surveyed the composition, temporal and spatial variation of periphytic algae, and temporal and spatial variation of the environmental factors of the Deganba riparian in Jiangjin of the upper reaches of Yangtze River (Deganba) from January to May2013, and November2013to January2014.. The purpose of this research will provide a scientific basis for protecting the ecological environment, and establish and develop a set of practical, concrete and effective measures in order to control water quality deterioration. The results were obtained as follows:(1) Within the investigation year,100species of periphytic algaes, under the membership of8divisions,55genuses, were distinguished in the Deganba riparian. These species were belonged to Bacillariophyta(58%), Chlorophyta(25%), Cyanophyta(7%), Euglenophyta(4%), Pyrrophyta(3%), Cryptophyta(1%), Chrysophyta(1%) and Xanthophyta(1%). The dominant population of periphytic algae was mainly Melosira, Cyclotella, Fragilaria, Synedra, Navicula of Bacillariophyta; Chlorella vulgaris, Ulothrix flaccidum, Sceaedesmus of Chlorophyta; Oscillatoria, Phormidium tenue, Chroococcus minor, Merismopedia punctata of Cyanophyta. Monthly variation of periphyton species composition showed that the number of species was presented the maximum in May2013, and followed in April2013, the lowest in December2013. The cell density of periphytic algae was reached the highest value in April, and the lowest in January. Species composition of periphytic algae displayed a significant spatial variation. The number of species composition was Sand pit> Farmland> Sand> Riverside.(2) The water quality parameters in the sampling sites showed that total nitrogen, total phosphorus content had reached the light eutrophication level. It has a single factor correlation relationship between the cell density and the total dissolved oxygen, or temperature, transparency, the total phosphorus content.(3) By the diversity index of periphytic algae in the Deganba riparian, We found that four sampling points diversity index points overall trend for Riverside> Farmland> Sand pit> Sand. Using indicator of periphytic algae, the water quality of the reserve can be monitored. The water was polluted and displayed lightly-eutrophication. Water in the area of Farmland, Riverside, and Sand is transited from P-mesosaprobic zone to a-mesosaprobic zone, and water in Sandpit area is transited from oligosaprobic zone to β-mesosaprobic.