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초록

This study aims to investigate the multigenerational (F0–F4) effects of biobased polylactic acid microplastics on the microbiota of the estuarine copepod Eurytemora affinis . High-throughput sequencing of 16S rDNA was used to assess shifts in host associated-microbiota composition, diversity, and functional potential, and to identify taxonomic biomarkers. Our findings demonstrate that exposure to polylactic acid microplastics at a concentration of 400 μg/L significantly altered the microbial diversity and composition of E. affinis . Alpha diversity was significantly reduced from second (F1) to fourth generation (F3) of the exposed groups, while beta diversity analyses revealed shifts in community structure without clear transgenerational clustering. Venn diagram analyses and taxonomic profiling showed divergence in amplicon sequence variants between control and exposed groups across generations, with potentials to recover in the decontamination generation (F4). Taxonomic biomarkers identified in exposed copepods through linear discriminant analysis effect size analysis indicated an enrichment of taxa such as the genera Pseudomonas and Mesorhizobium , which are associated with plastic degradation. Functional predictions using PICRUSt revealed enrichment of metabolic pathways related to fatty acid metabolism and degradation processes in exposed host-associated microbiota, suggesting shifts in the functional potential. Co-occurrence network analyses revealed stable microbial interaction networks. The decontamination generation exhibited potential recovery of the copepod-associated microbiota in the exposed group. This study is the first to investigate the multigenerational effects of polylactic acid microplastics on copepod-associated microbiota. Our results show that polylactic acid microplastics can cause disruptions in host microbial communities, with implications for host fitness and ecosystem functioning.

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