Presence of Anthropogenic Microplastics in the Leaves of Posidonia oceanica in the North Aegean Sea

The study of microplastics-MP in the aquatic environment has revealed their widespread distribution. Strong evidence exist that seagrass meadows act as traps and a possible pathway to the food chain. ExistingPosidonia oceanica studies focus almost completely on MP presence in the sediment, water column or spheroids, following different analytical protocols. In the present work, microplastic concentration on P. oceanica leaves was studied, from two N. Aegean Sea areas, following two different analytical protocols, optical analysis and sample digestion. We found a significant high number of MPs attached on leaves, making Posidonia meadows a significant hot spot, especially taking into account the extensive coverage of the species in the Mediterranean coasts. The variability of MPs between different areas showed the importance of local geomorphology and background MP concentration, while digestion is proposed as the preferred protocol, since 6 times more MPs were identified, in comparison to optical analysis.