Microplastics (MPs) have been found in nearly half of the fish samples collected from the field worldwide. There are feeding behavior differences caused by animal personality among fish individuals. However, how personality affects the exposure of fish to microplastics is unclear. In this study, adult zebrafish were used as a model to study the effects of fish personality (boldness) on MPs exposure. Experiment showed that zebrafish captured MPs actively when MPs were added to the system but spit part of the MPs out after capturing. Bold zebrafish had higher feeding activities, captured MPs more frequently and swallowed more MPs than shy zebrafish. Zebrafish ingested brine shrimp preferentially when both brine shrimp and MPs were provided at the same time, and less MPs were swallowed in co-ingestion situation. Spearman correlation analysis indicated that there is a significantly positive correlation between boldness and feeding MPs frequency. Results of this work demonstrate that zebrafish mistake MPs as food and capture them actively but can discriminate MPs as inedible substances after ingestion and spit part of the MPs out. Bold zebrafish have a higher MP exposure burden than shy zebrafish due to their difference in feeding behaviors. The influence of fish personality needs to be considered for future toxicity studies and risk assessment of fish exposed to MPs.

Background: Viruses play critical roles in the marine environment because of their interactions with an extremely broad range of potential hosts. Many studies of viruses in seawater have been published, but viruses that inhabit marine animals have been largely neglected. Oysters are keystone species in coastal ecosystems, yet as filter-feeding bivalves with very large roosting numbers and species co-habitation, it is not clear what role they play in marine virus transmission and coastal microbiome regulation.Results: Here, we report a Dataset of Oyster Virome (DOV) that contains 728,784 nonredundant viral operational taxonomic unit contigs (≥ 800 bp) and 3473 high-quality viral genomes, enabling the first comprehensive overview of both DNA and RNA viral communities in the oysterCrassostrea hongkongensis. We discovered tremendous diversity among novel viruses that inhabit this oyster using multiple approaches, including reads recruitment, viral operational taxonomic units, and high-quality virus genomes. Our results show that these viruses are very different from viruses in the oceans or other habitats. In particular, the high diversity of novel circoviruses that we found in the oysters indicates that oysters may be potential hotspots for circoviruses. Notably, the viruses that were enriched in oysters are not random but are well-organized communities that can respond to changes in the health state of the host and the external environment at both compositional and functional levels.Conclusions: In this study, we generated a first “knowledge landscape” of the oyster virome, which has increased the number of known oyster-related viruses by tens of thousands. Our results suggest that oysters provide a unique habitat that is different from that of seawater, and highlight the importance of filter-feeding bivalves for marine virus exploration as well as their essential but still invisible roles in regulating marine ecosystems.