Microplastics on beaches: ingestion and behavioural consequences for beachhoppers

Microplastics are ubiquitous in the marine environment worldwide, and may cause a physical and chemical risk to marine organisms. Their small size makes them bioavailable to a range of organisms with evidence of ingestion at all levels of the marine ecosystem. Despite an increasing body of research into microplastics, few studies have explored how consumption changes complex behaviours such as predator avoidance and social interactions. Pollutant exposure can result in alterations in behaviour that not only leads to sub optimal conditions for individual organisms but may also serve as a warning sign for wider effects on a system. This research assessed the impacts of microplastics on the ecology of coastal biota using beachhoppers (Platorchestia smithi) as model organisms. We exposed beachhoppers to marine-contaminated microplastics to understand effects on survival and behaviour. Beachhoppers readily ingested microplastics, and there was evidence for accumulation of microplastics within the organisms. Exposure tests showed that microplastic consumption can affect beachhopper survival. Individuals also displayed reduced jump height and an increase in weight, however, there was no significant difference in time taken to relocate shelter post disturbance. Overall, these results show that short-term ingestion of microplastics have an impact on survival and behaviour of P. smithi. A reduction in the capacity for beachhoppers to survive and function may have flow on effects to their local environment and higher trophic levels.