Interplay between micro-nanoplastics and dissolved organic matter in aquatic ecosystems: From eco-corona dynamics to...

The ubiquitous use of plastics has led to the inevitable coexistence and interaction of micro/nanoplastics (MNPs) and dissolved organic matter (DOM) in aquatic ecosystems, which will exert unavoidable impacts on the physiological and ecological functions of microalgae, the keystone primary producers. This review systematically synthesizes the effects and mechanisms by which DOM mitigates microalgal toxicity under MNPs coexposure, addressing the critical gap in understanding the toxicological interactions of DOM and MNPs. First, we evaluate recent advances in the dynamics of interactions between MNPs and DOM and their influencing factors. Next, we integrate relevant quantitative analyses to assess how environmental conditions and microalgal secreted DOM modulate the toxicological impacts of MNPs. Crucially, we identify four key mechanisms underpinning toxicity mitigation mediated by DOM. These include ecological corona formation to shield toxic sites, reactive oxygen species scavenging to alleviate oxidative stress, heteroaggregation regulation to reduce bioavailability, and adaptive extracellular polymeric substance secretion to enhance stress resilience. Notably, both natural and microalgae-secreted DOM reshape eco-corona composition and stability by accelerating MNPs photoaging and surface oxidation, thereby altering toxicity thresholds. Finally, the review identifies critical knowledge gaps and outlines future research directions, emphasizing the development of integrated databases, predictive models, ecologically realistic simulations, and long-term dynamic monitoring frameworks. This work elucidates DOM's dual role as an eco-corona dynamics modulator and environmental fate regulator and provides novel perspectives to holistically decipher behavioral trajectories of MNPs while enriching strategies for aquatic biodiversity conservation and ecosystem resilience.