Exploring the resilience of constructed wetlands to harmful algal blooms disturbances: A study on microbial response mechanisms

[Display omitted] •CWs showed a capacity of adapting to the harmful algal blooms (HABs) with long-term operation.•Pollutant-removal of CWs experienced a transition from fluctuation to stability during HABs.•CWs increased the abundance of Acinetobacter in resisting HABs disturbance.•Low-abundance species contributed vital roles in nitrogen removal under HABs disturbance.•Low DO levels increased microbial activity which helped restore CWs resilience during HABs. Constructed wetlands (CWs) have emerged as a promising environmentally sustainable technique for wastewater treatment. However, the susceptibility of CWs to disturbances caused by harmful algal blooms (HABs) raises concerns. This study aimed to investigate the impact of HABs on the pollutants’ removal performance of CWs and the response of rhizosphere microbial community. Results revealed that CWs possessed an adaptive capacity that enabled them to recover caused by HABs. The rhizosphere was found to stimulate the occurrence of Acinetobacter, which played a critical role to help resist HABs disturbance. This study also observed an increased dissimilatory nitrate reduction metabolic pathway which promoted denitrification and enhanced the nitrogen removal efficiency of CWs. Additionally, the structural equation model further suggested that dissolved oxygen exerted a significant influence on the microbial activities and then affected the pollutants removal performance. Overall, our findings shed light on the mechanism for CW stability maintenance during HABs disturbance.