Short-Term Exposure to Storm-Like Scenario Microplastic and Salinity Conditions Does not Impact Adult Sea Urchin (Arbacia punctulata) Physiology.

The effects of microplastic pollution on sea urchins has received little attention despite their ecological and economical importance. This is the first study to focus on adult sea urchins (Arbacia punctulata). These organisms were exposed to storm-like sediment resuspension of microplastic concentrations (9-μm polystyrene 25,000 spheres L) combined with salinity reductions (salinity 25 vs. 33) associated with high precipitation. Urchins were exposed to these parameters for 24 h before assessing righting times and for 48 h before assessing oxygen consumption rates. No significant impacts on urchin physiology were observed showing resilience to short-term exposures of storm-like induced microplastics and salinity. No microplastic particles blocked the madreporite pores indicating the active removal of particles by cilia and pedicellariae. Gut tissue samples indicated consumption of microplastics. Studies on more species are urgently required to determine their responses to plastic pollution to inform management decision-making processes.