On some physical and dynamical properties of microplastic particles in marine environment

Simplified physical models and geometrical considerations reveal general physical and dynamical properties of microplastic particles (0.5-5 mm) of different density, shape and size in marine environment. Windage of extremely light foamed particles, surface area and fouling rate of slightly positively buoyant microplastic spheres, films and fibres and settling velocities of negatively buoyant particles are analysed. For the Baltic Sea dimensions and under the considered idealised external conditions, (i) only one day is required for a foamed polystyrene particle to cross the sea (ca. 250 km); (ii) polyethylene fibres should spend about 6-8 months in the euphoric zone before sinking due to bio-fouling, whilst spherical particles can be retained on the surface up to 10-15 years; (iii) for heavy microplastic particles, the time of settling through the water column in the central Gotland basin (ca. 250 m) is less than 18 h. Proper physical setting of the problem of microplastics transport and developing of physically-based parameterisations are seen as applications. (C) 2016 Elsevier Ltd. All rights reserved.