Unleashing multi-omic approaches to address environmental microplastic hazards in marine polychaetes

The impact of an environmental microplastic mixture (< 100 μm) on marine polychaete was explored to simulate the plastic exposure patterns in the natural habitat. In this study, Hediste diversicolor was used to mimic a real scenario exposure model of five common types of widely distributed microplastics sampled from the southern Mediterranean Sea. Sediment and polychaete gut were collected for microbiome and metabolomic analysis. Interestingly, high-throughput sequencing revealed a shift in bacterial diversity depending on microplastic concentration (10, 100 and 1000 μg kg-1). Noteworthy, sediment revealed similar diversity with respect to the polychaete gut microbiome. Specific bacterial taxa, particularly Mesoflavibacter zeaxanthinifaciens and Vibrio cortegadensis, were notably affected, indicating adaptive responses to altered environments. The identification of different clusters of markedly altered metabolites, including indoles, benzene derivatives, coumarins, pyrones, flavonoids, cinnamates, diterpenes and sesquiterpenes, offered an insight into the physiological and pathological changes observed within the polychaete following microplastics exposure. These novel findings enhance our understanding of the intestinal hazards of environmental microplastics and underscore the potency of multi-omics investigations in unraveling the intricate mechanisms underlying microplastic toxicity.