Coexistence of cyanobacteria and microplastics in eutrophic lake ecosystems: Interactions and combined effects

Cyanobacteria and microplastics (MPs) inevitably coexist in eutrophic lake ecosystems, potentially posing considerable ­ecological risks. However, systematic summaries and discussions exploring their interactions and effects on ecosystem structure and function remain scarce. Herein, we provide a comprehensive overview of the biological effects of MPs on cyanobacteria, the impact of cyanobacterial biofouling on MP properties and behavior, and their combined effects on aquatic organisms and biogeochemical cycles in eutrophic lake ecosystems. MPs induce oxidative stress in cyanobacteria mainly through physical damage and stimulation of reactive oxidative species generation. Owing to the different sensitivities of different species to MPs, changes in cyanobacterial community composition and structure have been observed under coexposure conditions. Furthermore, cyanobacterial colonization can influence biofilm formation and accelerate the degradation and sedimentation of MPs. The coexistence of cyanobacteria with MPs in eutrophic lakes may exert additional stress on aquatic ecosystems, which are classified mainly as joint toxicity to aquatic organisms and long-term effects on biogeochemical cycles. Finally, we propose future research directions in this field, with particular emphasis on the profound combined and cascading effects of cyanobacteria and MPs on ecosystem structure and function. This paper offers valuable insights into the assessment and control of the integrated ecological risks associated with eutrophication and MP pollution.