Characteristics and Driving Factors of the Aerobic Denitrifying Microbial Community in Baiyangdian Lake, Xiong'an New Area.

Here, the ion-exchangeable form of nitrogen (IEF-N), weak-acid extractable form of nitrogen (WAEF-N), strong-alkali extractable form of nitrogen (SAEF-N), strong-oxidant extractable form of nitrogen (SOEF-N), residue nitrogen (Res-N), and total nitrogen (TN) showed spatial differences, and most of the sediment nitrogen fractions exhibited positive correlations in Baiyangdian Lake. High-throughput sequencing analysis revealed that the aerobic denitrification microbial community was composed of proteobacteria (42.04%-99.08%) and unclassified_bacteria (0.92%-57.92%). Moreover, the microbial community exhibited significant differences (R = 0.4422, < 0.05) on the basis of the adonis analysis. T(temperature), Moisture content (MC), sediment total phosphorus (STP), ion-exchangeable form of ammonia (IEF-NH-N), weak-acid extractable form of ammonia (WAEF-NH-N), weak-acid extractable form of nitrate (WAEF-NO-N), and strong-alkali extractable form of ammonia (SAEF-NH-N) were the dominant environmental factors and explained 11.1%, 8.2%, 10.7%, 6.9%, 9.3%, 8.1%, 10.5%, 7.5%, and 7% variation, respectively, of the total variation in the microbial community. Furthermore, the network analysis showed that symbiotic relationships accounted for a major percentage of the microbial networks. The keystone aerobic denitrifying bacteria belonged to , , , , , _Burkholderiales, , , unclassified_Burkholderiales, and unclassified_bacteria. The composition of the keystone aerobic denitrifying microbial community also exhibited significant differences (R = 0.4534, < 0.05) on the basis of the adonis analysis. T, STP, IEF-NH-N, ion-exchangeable form of nitrate (IEF-NO-N), WAEF-NO-N, SAEF-NH-N, and TN were the dominant environmental factors that explained 8.4%, 6.2%, 4.6%, 5.9%, 5.9%, 4.5%, and 9.4% variation, respectively, of the total variation in the keystone aerobic denitrifying microbial community. The systematic investigation could provide a theoretical foundation for the evolution mechanism of the aerobic denitrifying microbial community in Baiyangdian Lake.