Characteristics of Nitrogen Cycling Bacterial Community Structure in Sediments of the Third Drainage Ditch in Ningxia
Sediments are important sites of nitrogen cycling.To explore the characteristics of the bacterial community struc-ture involved in nitrogen cycling in the sediments of the Third Drainage Ditch in Ningxia,based on analysis of the physico-chemical properties of sediments at five sampling points,fluorescent quantitative PCR was used to determine the abundance of functional genes related to nitrification and denitrification,and correlation analysis was performed between the bacterial community and environmental factors.The results showed that except for the sediment at the starting point of the Third Drain-age Ditch with a pH value of 6.96,the sediments at other points exhibited weak alkalinity.Organic carbon,ammonium nitro-gen,nitrate nitrogen,total nitrogen,and total phosphorus showed a spatial distribution trend of decreasing and then increasing along the ditch.The abundance of AOB amoA genes(3.16×106～7.95×107 copies/g)in nitrifying bacteria was significantly higher than that of AOA amoA genes(5.62 ×103～3.76×105 copies/g).Concerning denitrifying bacteria,the abundance of nirS genes(6.87×107～9.16×108 copies/g)exceeded that of nirK genes(2.40×107～3.42×108 copies/g).The phylum Thaumarchaeota is the predominant group of ammonia-oxidizing archaea(AOA),while the phylum Proteobacteria is the major group consist-ing of both ammonia-oxidizing bacteria(AOB)as well as bacteria possessing nirK and nirS genes.The spearman correlation analysis between the nitrogen cycling microbial community structure in the sediments and environmental factors indicated a significant positive correlation between AOA and ammonium nitrogen(P＜0.05),as well as an extremely significant negative correlation between AOA and TOC(P＜0.001).AOB exhibited a significant positive correlation with pH,while nirS-type denitrifying bacteria showed a significant negative correlation with pH,and nirK-type denitrifying bacteria showed an extremely significant negative correlation with TOC.The results indicated significant differences in the bacterial community structure involved in nitrogen cycling in the sediments of the Third Drainage Ditch,and these were significantly influenced by physicochemical factors.
sedimentnitrogen cyclingbacterial community structureAOAAOBnirKnirS
万方数据
维普
