The Effect Of Artificial Forced Mixed Oxygenation On The Regulation Of Bacterial Community In Jinpen Reservoir

In order to compared with natural bacterial characteristics,we study the effect of the artificial forced mixing oxygen filling the adjustment role of bacterial community at Xi 'an Jinpen reservoir.This study combined with flow cytometry,Biolog technology and high-throughput sequencing technology.We monitored continuously water quality and the characteristics of the bacterial community in the reservoir.The main contents were: the evolutive characteristics of the bacteria quantity,the function diversity and the structure diversity in different water layers;the interaction between bacterial community and water quality in reservoir;the effect of bacterial community characteristics by operating the water-lifting aerator.The main conclusions are as follows:(1)During the natural mixing period,the number of bacteria and the proportion of HNA and LNA bacteria remained basically the same in surface,middle and bottom water.The utilization of carbon source by bacteria communities in different water layers tends to be uniform.The differences of the diversity index and population distribution of the water vertical bacterial community were small.At the phylum level,the main bacteria were Actinobacteria ? Proteobacteria and Bacteroidetes.At the genus level,the main bacteria were hgcl_clade and CL500-29_marine_group.(2)During the stratification period,the number of bacteria and the proportion of HNA bacteria in the hypolimnion layer were the most.The functional diversity of the bacterial community increased from the epilimnion layer to the hypolimnion layer;the utilization degree of carbon source in anaerobic layer bacterial community was higher than that in aerobic water layer;Shannon index and Chao1 index showed the rule of " metalimnion layer >hypolimnion layer > epilimnion layer ";the main phylogeny of bacteria in the water showed the trend of the largest number in the metalimnion layer and the smallest number in the epilimnion layer,the abundance of Actinobacteria increased from the epilimnion layer to the hypolimnion layer.The abundance of Synechococcus inceresed to 39.53%.And the abundance of Limnohabitans and Flavobacterium increased to 5.6%?3.64%,and the abundance of Methylobacter,Methylocystis,Polynucleobacter and Fluviicola were decreased to 0.01%?0.15%?0.31% and 0.09% in the hypolimnion layer.(3)RDA results showed that water temperature,TN and Mn were the main environmental factors affecting the distribution of bacterial community during the natural mixing period,while hgcI_clade ?Limnobacter?Pseudarcicella were the main bacteria that affected water quality.During the stratification period,the major environmental factors affecting the distribution of bacterial community were DO,T,TN,TP and Fe,while Methylobacter?CL500-29_marine_group?Pseudarcicella?Exiguobacterium were the main bacteria that affected water quality.(4)Due to the artificial forced mixing and oxygenating,the abundance index of ACE and Chao 1 and the diversity index Shannon increased significantly.The differences of bacterial community composition were reduced.The abundances of Actinobacteria and Proteobacteria gradually change from "middle > bottom > surface" and " surface > bottom > middle " to be consistent in the surface?middle and bottom water.At the same time,the gap of samples were decreased due to the aeration system operation.Because of the artificial mixing and oxygenation effect,the abundances of Synechococcus was reduced by about 66%.The abundances of Polynucleobacter ? Methylocystis ?Methylobacter increased to 1.06%?2.20%?1.96% in the bottom water,while abundances of Exiguobacterium and Flavobacterium decreased to 0.36%?0.12%.According to the redundancy analysis,the thermal stratification stability,water temperature,DO,TP and TN were the main factors affecting the bacterial community structure during the system operation.