Study On The Influence Of Different Discharge Patterns Of Urban Tailwater On Microbial Community Structure In The Surrounding Waters

The tail water produced by urban sewage treatment plants contains a large number of microorganisms,especially pathogenic bacteria.when discharged into the sea,it not only harms to the surrounding people,but also poses a threat to the ecological security of the sea.In this study,the sea water from three kinds of different discharge patterns were used as research objects.Bacteria,fungi,Arcobacter butzleri,Aeromonas lacus,Campylobacter curvus and Enterococcus hirae were analyzed.The effects of discharge patterns and tide on the microbial community structure in the sea water nearby were clarified.Results are as follows:(1)The results of quantitative showed that the number of sea water fungi in the four seasons is small.The number of bacteria in summer is the highest.Overall comparison,the number of samples discharged directly into the coastal sea area and discharged into the sea through a river firstly is higher than that discharged into deep sea.The number of bacteria is more sensitive to tides.The response to tidal conditions is basically the same under different temperature conditions,and the number of samples of ebb tide is much higher than that of high tide.The number of four typical pathogens in the four seasons was at least 10~5,and the number of Arcobacter butzleri was higher than the other three pathogens.The number of pathogens in spring and summer was higher than that in autumn and winter.The response of four typical pathogens to tides is consistent with the quantitative results of the bacteria..(2)The main phylum in the four seasons is the Proteobacteria.The relative abundance of Cyanobacteria,Bacteroidetes,Firmicutes and Actinobacteria are also relatively large.On the whole,although the temperature varies greatly with the seasons,the microbial community structure in the sea area around the same area has certain similarity at the phylum level.The relative abundance of Proteobacteria from samples discharged into deep sea is higher than the other two different discharge patterns.In fact,there is no obvious change regularity in the influence of tidal on the number and relative abundance in the phylum level.Relatively speaking,the absolute main phylum is less affected by the tide.(3)The main class in in the four seasons is the Gammaproteobacteria.The class of samples discharged into deep sea also including Alphaproteobacteria,Deltaproteobacteria,Betaproteobacteria,Epsilonproteobacteria,Chloroplast,Flavobacteria,Bacteroidia,Clostridia,Bacilli.The class of samples discharged into the sea through a river firstly also including Alphaproteobacteria,Deltaproteobacteria,Betaproteobacteria,Epsilonproteobacteria,Chloroplast,Nostocophycideae,Cyanobacteria,Flavobacteria,Clostridia,Acidimicrobiia and Actinobacteria.The class of samples discharged directly into the coastal sea area also including Alphaproteobacteria,Epsilonproteobacteria,Chloroplast,Flavobacteria,Nitriliruptoria and Bacilli.All in all,the change of temperature has a great influence on the microbial community structure in the class level.The microbial community structure in the sea area around the same area has larger similarity in the level of phylum than class.In fact,there is no obvious change regularity in the influence of tidal on the number and relative abundance in the class level.Relatively speaking,the absolute main class is less affected by the tide.(4)There are 36 kinds of pathogens were detected in in the four seasons,and the tides hardly affect the species of pathogens.In autumn,a mass of pathogens are found.In winter,only the pathogenic bacteria Trichococcus pasteurii,which causes diarrhea,is found.Although it is low in content,it has been active in various seasons.Indicating that the viability is extremely strong and our attention should be attracted.There are some pathogens have high frequency and content.Such as Stanieria cyanosphaera causing rhinitis and conjunctivitis,respiratory infection pathogen Aestuariibacter halophilus,intestinal infection pathogen Vibrio spp.,fish pathogen Pseudoalteromonas spp.,Enteropathogenic bacteria Arcobacter spp.,dermatological pathogens Epibacterium ulvae and Flavivirga amylovorans,Brucella microti cause fever,hyperhidrosis and joint hyperplasia.