Integrated toxicokinetic/toxicodynamic assessment modeling reveals at-risk scleractinian corals under extensive microplastics impacts.

Marine microplastics (MPs)-induced threats to shallow-water scleractinian corals are a growing global concern that needs interdisciplinary studies. However, it remains uncertain to what extent the ecotoxicological effects of MPs can explain the potential health impacts on corals at the species-specific scale. Using recent datasets of multiple MPs-induced impacts on coral species, we developed an integrated ecotoxicological modeling approach to quantify the MPs-corals interaction dynamics. Toxicokinetic (TK)-based corals ingestion, egestion, and adhesion processes posed by MPs were comprehensively evaluated. Based on estimated uptake and egestion rates, we showed that corals were much likely to bioaccumulate marine MPs. We applied toxicodynamic (TD) models to appraise time- and concentration-dependent response patterns across MPs-corals systems. We found that marine MPs are highly toxic to corals with a median benchmark concentration causing 10% compromised coral health of 20-40 mg L and a mean growth inhibition rate of ~2% d. By providing these key quantitative metrics that may inform scientists to refine existing management strategies to better understand the long-term impact of MPs on coral reef ecosystems. Our TK/TD modeling scheme can help integrating current toxicological findings to encompass a more mechanistic-, ecological-, and process-based understanding of diverse coral ecosystems that are sensitive to MPs stressor varied considerably by species and taxonomic group.