0
Article ? AI-assigned paper type based on the abstract. Classification may not be perfect — flag errors using the feedback button. Tier 2 ? Original research — experimental, observational, or case-control study. Direct primary evidence. Sign in to save

Hidden link between microplastic biofilms and aquatic nitrogen transformation: From regulator to diverse ecological effects

Ecotoxicology and Environmental Safety 2026
Zhijie Zheng, Tianyue Jin, Q Liu, L Wang, Jingchun Tang

Summary

This review pulls together existing research on how microplastics floating in lakes, rivers, and oceans become coated with slimy microbial communities (called biofilms) that can change how nitrogen pollution is processed in water. The concerning part: these microplastic biofilms can trigger the release of nitrous oxide, a potent greenhouse gas, while also potentially disrupting the natural nitrogen cycle that keeps aquatic ecosystems healthy. While this doesn't directly test effects on human health, it matters because it shows microplastics aren't just passive pollutants—they're actively reshaping water chemistry and ecosyst

As a vital carrier for the colonization and succession of diverse microbial communities, microplastics (MPs) surface form unique microplastic biofilms (MPBs) ecosystems. MPBs can enrich microorganisms involved in core nitrogen transformation processes, and the localized anoxic environment within these biofilms regulates nitrogen removal efficiency. Consequently, biofilms establish novel nitrogen transformation microenvironments within aquatic systems. Numerous studies have revealed that MPBs play a crucial role in key pathways of the nitrogen transformation. However, the potential regulatory role of MPBs in nitrogen transformation, along with the ecological risks and environmental applications arising from this process, warrants further review. A dual effect of MPBs has been identified in aquatic nitrogen transformation, presenting both ecological risks and environmental applications. MPBs promote multi-pathway coupling processes, such as nitrification and denitrification, by enriching functional microbial communities and constructing oxygen-gradient microenvironments. Incomplete denitrification and an imbalance in functional genes may significantly increase the risk of N₂O emissions from MPBs. Furthermore, biofilm succession under stress from environmental factors often accelerates the directional selection of functional communities and may alter the nitrogen balance in aquatic systems. Factors such as dissolved oxygen, DOM, and antibiotics can alter the final products of nitrogen transformation by regulating the expression of functional genes and the supply of electron donors. This paper reviews the general patterns of structural succession in MPBs, summarizes their primary ecological functions in the nitrogen transformation, and explores their underlying mechanisms from the perspective of regulation by environmental factors. The aim is to elucidate the potential impacts of MPs, as an emerging ecological niche, on nitrogen transformation processes in aquatic environments. This review deepens our understanding of nitrogen transformation functions and their environmental regulation mechanisms in MPBs, providing scientific support for aquatic environmental management and pollution control.

Share this paper