Microplastic pollution in stony coral skeletons and tissues: A case study of accumulation and interrelationship in South Penghu Marine National Park, Taiwan Strait.

Microplastics (MPs) pose a growing threat to coral reef ecosystems worldwide. However, data on MP contamination in coral reefs remain limited, hampering accurate ecological risk assessment. This study investigated MP contamination in coral reefs at South Penghu Marine National Park, analyzing 40 samples from 31 coral species. The average MP abundance was 0.32 ± 0.32 MPs/g wet weight, and the mean MP abundance in the coral tissues (0.26 ± 0.26 MPs/g ww) was significantly higher than that in the coral skeleton (0.08 ± 0.10 MPs/g ww). Most MPs were small (<1 mm: >60 %), fibrous (99.7 %), and primarily composed of rayon (59.8 %) and polyester (27.5 %). Significant correlations were found among MP abundance in whole corals, coral tissues, and coral skeletons. The correlation equation established in this study, linking coral skeleton, tissue, and whole corals, can facilitate a more comprehensive understanding of MP pollution level and its associated risks in coral reef environments. Notably, monofilament overgrowth was observed, highlighting the impact of nearby fisheries and recreational activities on MP contamination. These findings provide valuable field-based data on MP pollution levels and the associated risks to corals and offer a novel tool for assessing MP accumulation and potential risks in coral ecosystems.