| To explore the relationship between the change characteristics of substrate microbial community structure and physical and chemical properties,Illumina Mi Seq high-throughput sequencing technology was used to sequence and analyze the characteristics of substrate microbial community in each pool of the complex vertical flow constructed wetland in karst area.The results showed that the abundance and diversity of bacterial community showed a trend of first decreasing and then increasing.Proteobacteria,Firmicutes,Chloromycetes,actinobacteria,and Bacteroidetes were the dominant bacteria in the composite vertical flow constructed wetland.Firmicutes,δ-Proteobacteria,α-proteobacteria,γ-proteobacteria,and Clostridium are the characteristic microorganisms that flow vertically down the first-order pond to the biological oxidation pond.The abundance and diversity of fungal communities decreased first and then increased,similar to bacterial communities.The dominant phyla were Ascomycetes,Rozobacteria,basidiomycetes,chytridomycetes,and Sporomycetes.Trichoderma,Fusarium,Mortierella,Penicillium,and Sabelindena were the dominant species from the primary vertical flow pond to the biological oxidation pond,respectively.In the composite vertical flow constructed wetland,p H,dissolved oxygen,ammonia nitrogen,nitrate nitrogen,total nitrogen,and phosphorus affect bacterial and fungal community characteristics.Most bacteria and fungi are affected by multiple physicochemical factors,but the most significant influencing factors are p H,ammonia nitrogen,nitrate nitrogen,and total nitrogen.p H is a factor for many dominant bacteria genera of bacteria and fungi.63.16% of the affected bacteria are from Proteobacteria,and the most affected fungi are Amphiogloea and Colacogloea.Nitrogen is the main factor in changing bacterial and fungal community characteristics.For example,nitrate nitrogen and ammonia nitrogen significantly affect Xanthanomonas,Erythrobacter,and Rhizobium in bacteria and penicillium,Fusarium,and Basiliformis in fungi.In this complex vertical flow constructed wetland,p H,dissolved oxygen,ammonia nitrogen,nitrate nitrogen,total nitrogen,and total phosphorus affect bacterial and fungal community characteristics.Most bacteria and fungi are affected by multiple physicochemical factors,but the most significant influencing factors are p H,ammonia nitrogen,nitrate nitrogen,and total nitrogen.p H is a factor for many dominant bacteria genera of bacteria and fungi.63.16% of the affected bacteria are from Proteobacteria,and the most affected fungi are Amphiogloea and Colacogloea.Nitrogen is the main factor in changing bacterial and fungal community characteristics.For example,nitrate nitrogen and ammonia nitrogen significantly affect Xanthanomonas,Erythrobacter,and Rhizobium in bacteria and penicillium,Fusarium,and Basiliformis in fungi.In order to further understand the microorganisms related to wetland denitrification,the characteristics of Nirs and Nirk denitrifying bacteria communities and ammonia-oxidizing bacteria and archaea were analyzed.The results showed that in Nirs and Nirk denitrifying bacteria communities,the diversity and abundance of Nirs denitrifying bacteria were higher than that of Nirk denitrifying bacteria.Proteobacteria accounted for the highest proportion among the two types of bacteria.Thiobacillus,Magnetospirillum,Dechloromonas,and Soxella were the dominant species of Nirs bacteria in this wetland.The dominant genera of Nirk bacteria were Bradyrhizobium,Achromobacter,Rhodopseudomonas,nitrate-reducing bacteria,and Rhizobium sinensis.Nirs and Nirk bacteria were significantly affected by p H and nitrogen.In this wetland system,there were significant differences between the ammonia-oxidizing bacteria(AOB)and ammonia-oxidizing archaea(AOA)communities,with more AOB.The dominant bacteria of AOB are Proteobacteria,and the dominant bacteria genera are nitrovibrio and nitrovibrio.The dominant bacteria of AOA are Crenarchaeota and Thaumarchaeota.Both denitrifying microorganisms and ammonia-oxidizing microorganisms were significantly regulated by p H,nitrate nitrogen,ammonia nitrogen,and total nitrogen.According to this study,Xanthomonas,Rhodobacter,and Rhizobium were found in the bacteria.Fungi Penicillium,Fusarium,Basiliformis,Anthracoceras,and Plectosphaerella;Rhodopseudomonas and Rhodobacter in Nirs and Nirk denitrifying bacteria,as well as in AOA and AOB nitro vibrio and nitro vibrio,there are dominant strains involved in denitrification process,which also provide a basis for the maintenance,efficient nitrogen removal,and improvement of the surrounding ecological environment of composite vertical flow constructed wetlands. |
