Trophic transfer of polyester microfibres across a multi-level marine food web

Microplastics are multifarious contaminants and their transfer by marine organisms can impact health. Yet, despite considerable research, microplastic quantification across multiple trophic levels is incomplete. Here, ingestion, retention, depuration and transfer of environmentally relevant polyester (PEST) microplastics, with plasticising bis(2-ethylhexyl) phthalate (DEHP) as a co-contaminant, is reported for three reef species. Exposed copepods (Parvocalanus crassirostris), mysid shrimps (Mysida) and moon wrasse fish (Thalassoma lunare) ingested (<21.33 ± 15.94 PEST individual^-1), retained (<48 h), and depurated (<5.77 ± 1.27 PEST h^-1) PEST. Trophic transfer was observed as a 14.6-fold (copepods to shrimps) and 4.3-fold (shrimps to fish) increase of PEST. All organisms demonstrated PEST bioconcentration, PEST biomagnification only occurred in shrimp. DEHP positively influenced PEST intake by copepods, yet had no impact on PEST transfer. Demonstrated PEST transfer across this food chain, coupled with species-specific bioconcentration and biomagnification dynamics, enhances understanding of microplastics fate and informs ecological impact assessments.