Effect Of Combination Of Bellamya Aeruginosa And Myriophyllum Spicatum On Water Purification And Diversity Of The Attached Bacterial Community

In order to maintain the health of the grass-type lake ecosystem,improve the water environment and solve the problems of eutrophication of shallow lakes by biocenosis,Bellamya aeruginosa and Myriophyllum spicatum were used to discuss the effects of single species and their combination on water quality,from July to September of 2019.Based on the combination,their effect on water purification in different density was determined.Combining with high-throughput sequencing technologies,the paper analyzed the diversity and composition of bacterial community attached to plant Myriophyllum spicatum in different experimental groups,screened significantly different keystone phylum and genus,and made an RDA analysis between the abundance of attached bacteria and physicochemical factors.It is designed to provide basic data and theoretical foundation in protection and restoration of shallow lake.The main results were as follows:1.The combination of Bellamya aeruginosa and Myriophyllum spicatum improved the dissolved oxygen?DO?and pH,while reducing the concentration of turbidity?TUB?,ammonia nitrogen?NH₄⁺-N?and total nitrogen?TN?,significantly.Both single Myriophyllum spicatum and combination could remove total phosphorus?TP?from water,markedly.2.Under the condition of constant density of Mvriophyllum spicatum,low-density group of Bellamya aeruginosa significantly reduced the concentration of TP,mid-density group significantly inhibited the growth of phytoplankton and promoted the absorption and transformation of NH₄⁺-N,and TN;the high-density group reduced DO,significantly.3.Under the condition of constant density of Bellamya aeruginosa,the mid-density group of Mvriophyllum spicatum improved the content of DO and reduced TUB,the concentration of NH₄⁺-N and TN,high-density group markedly reduced the concentration of TP and inhibited the growth of phytoplankton.4.The sequencing results in different combination showed that:?1?Both in Bellamya aeruginosa's density experiment and Myriophyllum spicatum's experiment,28 phyla and 16genus were detected,which relative abundance was above 0.5%,the dominant phyla were Proteobacteria,Cyanobacteria and Bacteroidetes;each group had different dominant genus in different periods.?2?In the density experiment of Bellamya aeruginosa,the biomarkers belong to Proteobacteria,Firmicutes,Verrucomicrobia,Bacteroidetes,Spirochaetes,Chloroflexi and Chlamydiae.The redundancy analysis?RDA?suggested that the abundance of Proteobacteria was positive correlation with TUB,NH₄⁺-N,TP,TN and Chla;the abundance of Firmicutes was positive correlation with TUB,NH₄⁺-N,TP,TN and Chla;the abundance of Verrucomicrobia and Bacteroidetes was positive correlation with DO and pH;the abundance of Spirochaetes was positive correlation with DO,pH and NH₄⁺-N;the abundance of Chloroflexi was positive correlation with DO and the abundance of Chlamydiae was positive with DO and NH₄⁺-N.?3?In the density experiment of Myriophyllum spicatum,the biomarkers belong to Proteobacteria,Firmicutes,Verrucomicrobia,Bacteroidetes,Spirochaetes and Tenericutes.The abundance of Proteobacteria was positive correlation with TUB,NH₄⁺-N,TP and Chla;the abundance of Firmicutes was positive correlation with DO,pH,TUB and Chla;the abundance of Verrucomicrobia was positive correlation with TUB,NH₄⁺-N,TP,TN and Chla;the abundance of Bacteroidetes was positive correlation with TP and TN;the abundance of Spirochaetes was positive correlation with DO,TUB,NH₄⁺-N,TP and Chla;the abundance of Tenericutes was positive correlation with TUB,NH₄⁺-N,TP and Chla.In conclusion,the combination of Bellamya aeruginosa and Myriophyllum spicatum improved DO and pH,and removed the NH₄⁺-N and TN;mid-density of them improved water quality by removing NH₄⁺-N and TN in water,markedly;high-density of Myriophyllum spicatum marked effects on removing the TP.In different water environment,there were significant differences in community composition of attached bacteria,physicochemical factors of water played an important role in the change of attached bacterial community.