Microbial abundance and community in constructed wetlands planted with Phragmites australis and Typha orientalis in winter

In winter, the withering of plants in constructed wetlands (CWs) limits the removal of pollutants by plants. It is prospective to improve performance of CWs through targeted transformation of the microbial abundance and community. This research characterized the purification performance of CWs planted with Phragmites australis (P. australis, PA) and Typha orientalis (T. orientalis, TO) and those in the unplanted constructed wetland (CT, control). PA showed some superiority in the removal rates of COD and NH4 (+)-N (42.06% +/- 4.25% and 70.51% +/- 1.46%, respectively). The 16S rRNA gene copy numbers (7.60 +/- 0.57 x 10(4) copies/g) and the ammonia oxygen bacteria (5.30 +/- 0.06 x 10(3) copies/g) were the highest in PA. In microbial structure, compared with TO and CT, in addition to common microorganisms that can remove contaminants, many specific functional genera were detected in PA (Rhodobacter, Catellibacterium, Hydrogenophaga, Geothrix and Aeromonas), which promoted the removal of NH4 (+)-N and COD. Novelty statement The microbial abundance and communities were characterized in CWs with different plant species during winter. Better removal efficiency with high microbial abundance and diversified microbial community were found in CWs planted with Phragmites australis. This study confirmed that in winter, withered plants in CWs can effectively remove NH4 (+)-N and COD by affecting microbial abundance and community structure.

Automated summary

This study found that in winter, artificial wetlands planted with Phragmites australis had higher microbial abundance and a more diversified microbial community, leading to better removal efficiency, especially in the removal of ammonia nitrogen and COD.