Understanding through drone image analysis the interactions between geomorphology, vegetation and marine debris along a sandy spit.

Marine litter (ML) is recognized as one of the main socio-economic and environmental concerns and monitoring operations have been realized worldwide in order to collect information on the types, quantities and distribution of marine debris. In this study, we used Unmanned Aerial Vehicle (UAV) images to map the presence of ML on a coastal spit in relation to geomorphological aspects and vegetation. Our results show that ML is present everywhere, but concentrates in the beach wrack, dunes, and saltmarshes, highlighting the role of the vegetation in trapping ML. Moreover, ML will most probably remain trapped by the saltmarsh vegetation, since they are not visible and easily accessible to allow cleaning operations. On the contrary, cleaning operations may remove the ML present in the beach wrack. Finally, our results provide useful information to support decision-makers for improving beach cleaning activities in the Po river Delta areas (Italy).

What can beach litter tell about local management: A comparison of five pocket beaches of the North Sardinia island (Italy).

Our study provides a first dataset on marine litter collected at five pocket beaches situated in the northern Sardinia (Italy). The monitoring method refers to the operational guidelines for rapid beach assessment of beach waste described by UNEP. We classified the 7975 items collected according to the eight categories and 99 types. Their analysis indicates that plastic is the most common litter category and, plastic fragments are the most frequent debris. The density ranges from 0.05 to 2.82 item/m2. The top 10 highly present marine litter reveals that land-based litter is the main source, probably due to the lack of waste management, massive tourism and recreational activities. In addition, landscape morphology affects the redistribution of marine litter. Overall, these first results are part of a wider study on the presence of marine litter in the pocket beaches of north Sardinia to provide coastal managers and policy makers mitigation strategies.

Examining the dependence of macroplastic fragmentation on coastal processes (Chesapeake Bay, Maryland).

Plastic debris in the coastal environment is subject to complex and poorly characterized weathering processes. To better understand how key environmental factors affect plastic degradation in a coastal zone, we conducted an in situ experiment. We deployed strips of high density polyethylene (HDPE) and polystyrene (PS) in paired coastal areas of contrasting conditions (hydrodynamic activity: erosional or depositional; water depths: subtidal or intertidal). Strips were collected after environmental exposures at 4, 8, and 43 weeks and analyzed for change in mass, algal biofilm growth, and imaged by petrographic and electron microscopy (SEM-EDS). Significant surface erosion was evident on both polymers, and was more rapid and more extensive with PS. Degradation of PS was responsive to intensity of hydrodynamic activity, and was greater at intertidal depths, highlighting the critical role played by photo-oxidation in the coastal zone, and suggesting that algal biofilms may slow degradation by playing a photo-protective role.