Distribution Pattern Of Benthic Diatom And Correlation To Its Environmental Factors In The Yinghe River, Huaihe Basin

Yinghe River, the largest tributary in the left bank of the middle reaches of the Huaihe River and seriously polluted, is the key water ecosystem restoration of the Huaihe Basin. Benthic diatoms are indispensable important link of the water ecological system in the energy flow and material cycle, which can directly or indirectly reflect the status of water environment, as the biological indicator, used in monitoring water environment. Therefore, the study of basin benthic diatoms has important ecological and social significance. In 2013, when normal river flow period, the Yinghe River System was set up 53 sample sites in the investigation to collecte benthic diatom samples. The emphasis is to analysis the dominant benthic diatom species, benthic diatom composition and distribution pattern, and to analysis the relationship between benthic diatom and environmental factors, and to discuss the function of benthic diatoms in monitoring water quality and controlling water pollution. It provides basic data and biological basis for the Yinghe River System, and even the Huaihe River in aquatic ecology, water quality mo nitoring and water pollution governance. The main results were as follows:1. Identification of diatom is 370 species and varieties, belonging to 56 genera 6 orders. Navicula, Nitzschia, Gomphonema and Achnanthedium are rich, respectively for 71 species(19.19%), 49 species(13.24%), 46 species(12.43%), and 37 species(10.00%). Dominant species are seven: Nitzschia inconspicua, Achnanthedium minutissimum, Navicula aitchelbee, Nitzschia palea, Cyclotella meneghiniana 、Navicula submuralis and Mayamaea atomus. Among of them, A. minutissimum can better respond the distribution of low nutrition water of the Yinghe River System, and Nitzschia palea, N. inconspicua and Navicula aitchelbee are the indicative species of eutrophication status of Yinghe River.2. The Strahlar method is adopted to divide the Yinghe River into 5 grades. In first order river, 12 genera 25 species are observed, 6 species are dominant, among of them, Cocconeis plancentula and Reimeria sinuata have the highest dominance; in seond order river includes 51 genera 243 species, 5 species are dominant, among of them, Achnanthedium minutissimum has the highest dominance; in third order river incudes 43 genera 229 species, 4 species are dominant,while the difference of the four dominant species dominance is small; in fourth order river includes 30 genera 100 species, 7 species are dominant, while Mayamaea atomus, Nitzschia inconspicua and Navicula aitchelbee have higher dominance in the dominant species; in fifth order river includes 38 genera 116 species, 8 species are dominant, while Nitzschia inconspicua has the highest dominance. It is increasing from first to second and third and then presents decrease that the number of species at all orders. That may be associated with second and third order rivers most flowing through the village, which the trophic levels of their environment is more rich than order 1, 4, and 5 river, that makes the competition between various benthic diatom smaller, not easy to form a single dominant species.3. Yinghe River System is divided into three areas according to total nitrogen(TN), total phosphorus(TP), ammonia nitrogen(NH3-N): Y-1 area includes the Ganjianghe River, Lihe River, Beiruhe River and Shahe River, the main nutrient had the lowest levels, benthic diatoms includes 46 genera 241 species, 7 species are dominant, while Achnanthedium minutissimum has the highest dominance; Y-2 area includes the Yinghe River which is the above part of zhoukou, Q ingyihe River, Shuagjihe River and Jialuhe River, the main nutrient level is highest, benthic diatoms includes 44 genera 210 species, 7 species are dominant, while Navicula aitchelbee, Navicula aitchelbee, Nitzschia immediate have the highest dominance; Y-3 area includes Fenquanhe River, Xincaihe River, Heicihe River and Yinghe River which is the following sections of zhoukou, the main nutrient level is in the middle and benthic diatoms includes 32 genera 167 species, 5 species are dominant, while Nitzschia inconspicua has the highest dominance. The maximum number and weight of the benthic diatom biomass in the Y-1 is 9.2×105 million/m2, and 4651.58 mg/m2; while the Y-3 area is the lowest,the number respectively is 2.2×105 million/m2, 980.09 mg/m2.4. Pearson correlation analysis indicates that it is very significant correlation between the conductivity(Cond), salinity(Sal), TN, TP, NH3-N with dominant species and diatom indices; it is significant positive correlation between Navicula aitchelbee, Nitzschia palea, Cyclotella meneghiniana with Cond, Sal, TN, while water temperature is showed a significant negative correlation with them.5. Dominant species of Yinghe River present a low nutrient and light interference—high nutrition—high nutrition and high interference distribution state from Y-1 to Y-3. The evaluation of Yinghe River System, as a whole,is in a state of heavy eutrophication level and heavy pollution by using physical and chemical factors and diatom biotic indices.