Impacts of microplastic ingestion on fish communities in Haizhou Bay, China.

Microplastics are pervasive throughout aquatic ecological communities. While their negative impacts on the life history traits of aquatic species are well studied, the effects on community dynamics remain elusive. Consequently, community-level assessments of microplastic effects on marine food webs are largely lacking, creating significant knowledge gaps regarding marine ecosystem structure and dynamics in the context of microplastic contamination. Here we expand a multispecies size-spectrum model by incorporating microplastic impacts on individual life-history traits, ultimately allowing us to study microplastic-mediated structural and functional changes in fish communities. As expected, microplastic ingestion may drive species extinction, but the microplastic-to-food ratio threshold for extinction is species-specific, and not necessarily correlated with species' asymptotic weights. Interestingly, species responses to microplastics also propagate through the community as ingestion triggers both bottom-up and top-down effects on community dynamics. Which specific type of cascading effect is dominating depends on which species is ingesting microplastics as well as its trophic role in the community. Generally, low-trophic-level species ingesting microplastics can exert large detrimental effects on community biomass. Thus, this study highlights the necessity for a comprehensive risk assessment of species-specific responses to microplastic contamination as well as an understanding of individual species' role in their communities.
Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Lai Zhang reports financial support was provided by National Natural Science Foundation of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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