Bioturbation alters nitrogen cycling in surface flow constructed wetlands: insights into microbial mechanisms

This study compared impact of benthic fauna on nitrogen (N) cycling processes in two type plants surface flow constructed wetlands (SFCWs) by field experiment in one year. Results determined that bioturbation altered proportion of N removal pathways in two type plants SFCWs. In winter, proportion of microbial processes in snail SFCWs increased, compared with non-snail SFCWs, were more 75%. In both two type plants SFCWs, relative abundance of Chloroflexi increased to 18.58% in summer and autumn. However, bioturbation had little effect on ɑ diversity. Bioturbation enhanced proportion of positive correlation in the networks between microbial taxa and decreased negative correlation in the networks between microbial taxa, suggested that promoted microbial community stability and interaction. Additionally, water properties, plant total nitrogen (TN) and sediment TN were the main factors driving microbial community change in snail SFCWs. These results highlighted microbial community dynamics under bioturbation in different season.