Role of Ammonia-Oxidizing Archaea in Ammonia Removal of Wetland Under Low-Temperature Condition

Ammonia-oxidizing archaea (AOA) have aroused great attention since it can supplement nitrogen cycle and show extensive existence relative to its bacterial counterpart, ammonia-oxidizing bacteria (AOB). This study compared the abundance and community compositions of AOA and AOB between natural and constructed wetlands under low temperature. More complex community structures were obtained in the constructed wetland, which may be ascribed to the differences in available nutrient contents. Nitrosospira-like organisms predominated AOB communities in both wetlands. Nitrososphaera cluster dominated the AOA community in the constructed wetland, while both Nitrososphaera and Nitrosopumilus clusters were dominant in the natural wetland. AOA dominated over AOB in both the natural and constructed wetlands, and AOA to AOB ratio ranged from 1.47 to 8.13. The natural wetland showed higher nitrification potential at low temperature, mainly due to its higher AOA to AOB ratio. This also explained why a better ammonia treatment performance was observed in the natural wetland even when it had high influent concentrations. The present results provided some new insights to ammonia removal in the wetlands under low temperature.