Resilient invaders: The exotic species' role in mitigating microplastics and perfluorooctanoic acid pollution

Does the vector role of invasive species exacerbate the stress risks posed by emerging contaminants during the process of biological colonization? In this study, a 21-day mesocosm experiment was conducted to investigate the effects of polystyrene microplastics (PS) and perfluorooctanoic acid (PFOA) on the invasive potential, photosynthesis, and water purification capacity of the exotic submerged plant Elodea canadensis. The results demonstrated that PS-PFOA composite pollution exhibited significant synergistic toxic effects, primarily by inhibiting photosynthetic efficiency, disrupting nitrogen metabolism, and exacerbating oxidative stress. This study identified a unique compensatory growth mechanism: exposure to PS (10 mg/L) and PFOA (20 μg/L) significantly increased chlorophyll b (20.47 %), carbon uptake (4.69 %), and phosphorus uptake (18.96 %) in E. canadensis, thereby maintaining growth under stress conditions. Furthermore, E. canadensis contributed to pollutant attenuation through synergistic interactions with dominant microbial taxa, indicating adaptive cooperation between plant and microbial communities. The observed increase in TP levels was attributed to enhanced microbial metabolic activity and associated physicochemical processes. These findings highlight previously underexplored adaptive strategies of invasive plants and microbial collaboration under dual-contaminant stress, offering novel insights into the ecological functions of invasive species and their implications for risk assessment and aquatic ecosystem restoration.