The Seasonal And Spatial Variations In Diatom Communities And The Influence With Environmental Factors In Three Temperate Reservoirs In Shandong Province,China

The South-to-North Water Diversion Project is a strategic measure to fundamentally solve the water shortage in North China.Datun Reservoir,Donghu Reservoir and Shuangwangcheng Reservoir are located in the east route of the Project.As the important drinking water source in Shandong Province,the water quality of the three reservoir is very crucial.However,there are currently few studies on the water quality conditions and the planktonic diatom population in three reservoir.Therefore,we analyze the water quality of the three reservoirs,the relationship between the diatom population structure and its relationship with environmental factors,and the difference of the diatom population structure among the three reservoirs can fill the water quality and diatom research of the three reservoirs.The conclusion also provides theoretical basis and technical support for the subsequent management and the prevention and control of diatom blooms.In this study,the water quality and planktonic diatoms of three reservoirs were monitored from April 2014 to April 2018.The variation of diatom composition,density and dominant species abundance were analyzed.The diversity and stability of the diatoms are illustrated by the diversity index and the uniformity index.Through the redundancy analysis and Pearson correlation analysis,the main environmental factors affecting the diatom population composition of each reservoir were identified.The non-metric multi-dimensional scale analysis combined with cluster analysis was used to compare the differences of diatom populations among three reservoirs.The imain conclusions are as follows.(1)A tota]of 58 species belong to 23 genera were detected in three reservoirs in Shandong Province.The main dominant diatoms of the three reservoirs are Synedra The diatom diversity is relatively small and the uniformity is relatively high in three reservoirs.The diatom density and proportion vary greatly.(2).The water temperature of each reservoir has obvious seasonal succession regulation,and the dissolved oxygen concentration has a negative correlation with water temperature.All three reservoirs are of weak alkaline water quality.The water level fluctuation and the water depth change range are relatively small.The three reservoirs were in a medium nutrient-mild eutrophic-moderate eutrophic state during the monitoring period.(3)The dominant diatoms of the three reservoirs are Synedra.There is a positive correlation between Synedra and total phosphorus in Datun reservoir.Synedra was significant positive with water temperature,CODMn and total nitrogen in Donghu Reservoir.(p<0.05).The Synedra in Shuangzhencheng Reservoir was positively correlated with water temperature(p<0.05).(4)The diatom community structure are similar in three reservoirs.The diatom community in 2014 was somewhat different from that in 2015.After 2015,the diatom population was basically stable,and the diatom population composition was basically similar.