The presence of microplastics affects Sepiella maindroni hatching performance and microbiota colonization

Microplastics (MPs) are a global concern regarding environmental pollution. This study evaluated the impacts of MPs with two sizes (5 µm and 0.5 µm) on hatching performance and microbiota of Sepiella japonica. The presence of MPs increased the hatching rate at some stages of the fertilization process and reduced the oxygen consumption rate at the gastrula stage. No size-dependent impact was observed. The 16S rRNA gene was sequenced to identify the flora. Clustering tags assessed species diversity in the samples with 97% similarity. Proteobacteria was the most abundant phylum in all three groups. MPs publicity appreciably modified flower structure. The most variable genera were Ralstonia, Methylophilus, and Pseudorhodoferax, which can furnish nutrients and modify the host’s immune response. MPs exposure appeared to enrich beneficial bacteria in this study. The presence of MPs with a size of 5µm played a greater role in this process, which is supported by presumptive functions. However, since the adsorption of suspended MPs on aquatic eggs can have cascading effects on specific life stages of oviparous animals, regular monitoring of microbial communities is necessary after juvenile S. japonica formation to prevent disease outbreaks.