[Nitrogen Metabolism and Flora Characteristics of Bacteria Algae Complex System].

In order to denitrify the urban tail water deeply and control the eutrophication of surface water, the molecular biology methods were used to study the nitrogen metabolism performance of the denitrification complex flora and the algal-bacteria symbiotic system. The results showed that the nitrogen metabolism complex flora was high ammonification and denitrification performance. The removal effect of ammonia nitrogen of group JZ was very well in urban tailwater, and the degradation rate was as high as 95%. The removal effect of total nitrogen of group JZ was better than that of group J in the experimental water distribution. High-throughput sequencing showed that the main dominant flora and proportion of group J were Firmicutes 44.53%, Proteobacteria 43.41%, Actinobacteria 5.37%, Bacteroidetes 3.04%, and Chloroflexi 1.35%. The main dominant bacterial groups in the group JZ were 33.89% Cyanobacteria, 25.34% Chloroflexi, 19.38% Proteobacteria, 10.02% Firmicutes, and 4.20% Acidobacteria. The dominant species in group J were compared with those in group JZ; the proportions were 82% and 18% in Firmicutes, 69% and 31% in Proteobacteria, 1% and 99% in Cyanobacteria, 5.1% and 95% in Chloroflexi, 73% and 27% in Actinobacteria. It was concluded that the removal effect of ammonia nitrogen of group JZ was high in the urban tailwater. With the addition and growth of Micrococcus in group J, the nitrogen metabolism flora in group JZ changed accordingly, so as to adapt to the environment in which the dominant algae formed. It forms a new nitrogen metabolism system of bacteria and algae with Micrococcus. This research provides a theoretical and data basis for the application of algal-bacterial co-metabolism systems.

[Effects of Water Supply Quality and Social Activity on the Microbial Community in Baiyangdian Wetland].

To clarify the impact of water quality and social activity in the Baiyangdian wetland on the biological community, the change characteristics of bacterial, fungal, and archaeal communities in different areas of the Dian District were studied. Samples were collected at the entrance of Fuhe District (NBB), tourist areas with frequent human social activities (NBD), residential breeding areas (NBX), and village sparse areas (NBN). The physical and chemical characteristics and biological communities of the samples were evaluated. The results of the study show that the COD concentration of organic pollutants in the NBB was 12.35 mg·L-1, and the total nitrogen concentration was 10.12 mg·L-1, that the concentration was highest. Moreover, the water quality in NBD and NBX was better than that of NBB. The NBN area exhibited the best water quality, with COD and total nitrogen concentration values of 6.9 mg·L-1 and 1.82 mg·L-1, respectively. Many types of NBB bacteria were recorded, with a diversity index of 5.86, and NBN diversity index exceeding 4.78. The dominant bacterial flora in all samples was the Proteobacteria, which accounts for 68.8% of the total bacterial communities in NBN samples. The diversity index of fungi in NBB was only 2.14. There were many types of fungi in NBN, with a diversity index of 3.23. Chytridiomycota was found in the NBD and NBN, accounting for 5.4% and 9.8% of the total number of fungi, respectively. The Chytridiomycota was main decomposer of hard to degrade organic carbon. The diversity of archaea of NBN was the lowest among all the samples. Crenarchaeota was the dominant phylum, which accounts for 39.0%, 51.9%, 47.3%, and 30.1% of NBB, NBD, NBX, and NBN samples, respectively. The number of Halobacterota was lower than Crenarchaeota. The main factor of eutrophication and microbial community changes in Baiyangdian wetland was the results of the combined action of external and internal pollution. Both external and internal pollution increased the organic matter, nitrogen and phosphorus content in the water, and the microbial community structure has changed significantly. The contents of organic matter, nitrogen, and phosphorus in water were increased and the microbial community structures were changed significantly by the increase of both external and internal pollution.