Impacts of microplastics on coastal biota and the potential for trophic transfer

Microplastics are ubiquitous in the marine environment worldwide, and pose a physical and chemical risk to marine organisms. Their small size makes them bioavailable to a range of organisms with evidence of ingestion across the food chain. Despite an increasing body of research into microplastics, few studies have explored how consumption changes complex behaviours such as predator awareness and sociality. Furthermore, our understanding surrounding the trophic transfer of associated microplastic contaminants and the resultant effects on the food web remain largely unknown. My research assessed the impacts of microplastics on the ecology of marine biota and the potential for trophic transfer using coastal ecosystems as a model. Beachhoppers (Platorchestia, smithi) readily ingested microplastics with subsequent alterations in behaviour. Contaminated beachhoppers were fed to Krefft’s frillgobies (Bathygobius, krefftii), and changes in personality were assessed. There was no effect on fish personality due to an increased plastic diet suggesting trophic transfer of microplastic is not an additional exposure pathway for contaminants. This study suggests consumption of microplastics may compromise some behaviours necessary for survival. While in the short term there is no behavioural evidence of trophic transfer, further studies should seek to understand the longer term effects of microplastics and their effect on the food web.