Ingestion, egestion and physiological effects of polystyrene microplastics on the marine jellyfish Rhopilema esculentum

Jellyfish are planktonic predators that may be susceptible to ingesting microplastics. However, the effects of MP exposure on jellyfish are poorly understood. In this study, the ingestion and egestion of polystyrene microbeads, and its chronic physiological effects on Rhopilema esculentum at an environmental concentration (100 items/L) and a predicted concentration (1000 items/L) were evaluated. The results showed that the ingestion amount of juvenile medusae was relatively low. The MP egestion rates reached 100 % within 9 h of clearance. Chronic exposure (15 days) to MPs at environmental concentrations led to no adverse impacts. Nevertheless, the pre-dicted concentration of MP exposure induced growth inhibition, a reduction in assimilation efficiency, oxygen consumption increase, and lipase enzyme activity reduction in the jellyfish, indicating that MPs can cause adverse effects on the energy budget of jellyfish in the near future. Our study provides new insights into the potential risk of MPs in marine environments.