Microplastics impair the feeding performance of a Mediterranean habitat-forming coral

The impact of plastic debris, and in particular of microplastics (here referred as particles smaller than 5 mm) onaquatic environments has now become a topic of raising concern. Microplastics are particularly abundant in theMediterranean Sea, potentially exerting substantial pressures on marine organisms at different levels of organization.Ingestion of microplastics has been observed in a large number of marine species. The aim of this workis to test if microplastics produce a feeding impairment in Astroides calycularis, a shallow water, habitat-formingcoral endemic to the Mediterranean Sea. Our findings suggest a lack of any avoidance mechanism allowing thepolyps to discern between food items and microplastics when occurring simultaneously. Moreover, polyps spenda considerable amount of time on handling microplastic particles. As a consequence, microplastics impair thefeeding efficiency in A. calycularis, since polyps may not be fully able to profit from the drifting plankton aggregations.Therefore, we suggest that microplastics can cause a reduction of fitness in A. calycularis, and presumablyalso in other species characterized by suspension feeding strategy.