Bioconcentración.xlsx

Context: Microplastics are ubiquitous in the global ocean and can be ingested by many species, including zooplankton. Although they exist within the size range typically associated with zooplankton prey, few in situ studies have been conducted on their ingestion. Aim: To evaluate the bioavailability and bioconcentration of microplastics in seven representative zooplankton taxonomic groups within a Marine Protected Area (MPA) in the Caribbean. Methods: Samples for microplastic bioavailability and bioconcentration analysis were collected from water and zooplankton during two contrasting hydroclimatic seasons in 2022. Key Results: A median microplastic bioavailability of 0.091 microplastics/m³ was recorded (mainly polyester and PET fibers and fragments), with significant seasonal differences (Kruskal-Wallis, p = 1.5×10⁻⁹). Zooplankton ingested mainly black fragments with an encounter rate ranging from 0 to 0.22 microplastics/individual. Bioconcentration in zooplanktonic groups was >1, indicating direct or indirect accumulation. Conclusion: The bioavailability of microplastics in the MPA is lower than in other global regions, with temporal variability modulated by Caribbean oceanographic dynamics and riverine inputs. Six of the seven zooplankton groups analyzed accumulated microplastics, Paracalanidae showing the highest bioconcentration factor. Implications: We provide information on bioacumalutation of microplastic in zooplankton , these findings underscore the need to monitor and mitigate the effects of microplastics on marine ecosystems to protect both the affected species and the ecosystem services they provide.