Data from: Impacts of weathered microplastic ingestion on gastrointestinal microbial communities and health endpoints in fathead minnows (Pimephales promelas)

Microplastics are a ubiquitous presence in the world’s aquatic
environments and their threat to aquatic biota is poorly understood,
especially in freshwater ecosystems. In the environment, microbial
biofilms can form on the surface of microplastics, and these plastics have
the potential to adsorb harmful toxins. Because lab-based studies on
microplastics are often conducted with clean polymers, in ecologically
unrealistic conditions and concentrations, the impact of these weathered
microplastics on aquatic organisms in ecologically realistic conditions is
still unclear. To help address the need for ecologically relevant
microplastic exposure data, we incubated 500 μm polyethylene microplastic
beads in Muskegon Lake, Michigan, USA and used them to conduct a 28-day
ingestion study with male and female fathead minnows (Pimephales
promelas). We examined the effects of microplastic ingestion on the fish
gut microbial community along with hepatic gene expression and health
parameters. We found that microplastic ingestion had statistically
significant impacts on growth in male fathead minnows. Microplastic
treatment did not significantly alter the beta diversity of the gut
microbial community for either males or females, but there were clear
differences between sexes and over time, indicating that these factors may
outweigh the impacts of microplastic ingestion on beta diversity in the
gut. The expression of immune response genes was not altered in males. It
did, however, cause some changes to alpha diversity metrics in both sexes
and there were several differentially abundant taxa among treatments.
These data suggest that microplastic ingestion has health effects, but
these effects may be sex specific across certain species and they are
likely not being solely driven by changes in gut microbial communities.