Millions of tons of riverine plastic waste enter the ocean via estuaries annually. The plastics accumulate, fragment, mix and interact with organisms in these dynamic systems, but such processes have received limited attention relative to open-ocean sites. In this Perspective, we discuss the occurrence and convergence of microplastics at estuarine fronts, focusing on their interactions with physical, geochemical and biological processes. Microplastic transformation can be enhanced within frontal systems owing to strong turbulence and interactions with sediment and biological particles, exacerbating the potential ecosystem impacts. The formation of microplastic hotspots at estuarine fronts could be a target for future plastic pollution mitigation efforts. Knowledge of the mechanics of plastic dispersal, accumulation and fate in frontal zones will, in turn, improve our understanding of plastic waste along the land–sea aquatic continuum.
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We thank X. Li for her assistance with the illustration in the original Figs. 2 and 3. Funding support was provided through the Asia-Pacific Network for Global Change Research (CRRP2021-08MY-Zhao to T.W., R.M.A. and S.Z.). This study was also supported by the National Natural Science Foundation of China (42076006) and by the European Union’s Horizon 2020 Research And Innovation Programme under a Marie Skłodowska-Curie grant (PLOCEAN 882682 to L.G.), an International Partnership Research Grant (UMT 55379 to R.M.A.) and the National Research Foundation Singapore through the Marine Environmental (to M.C.).
The authors declare no competing interests.
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Wang, T., Zhao, S., Zhu, L. et al. Accumulation, transformation and transport of microplastics in estuarine fronts. Nat Rev Earth Environ 3, 795–805 (2022). https://doi.org/10.1038/s43017-022-00349-x
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