Modelled transport of benthic marine microplastic pollution in the Nazaré Canyon

[摘要] With knowledge of typical hydrodynamic behavior of waste plastic material,models predicting the dispersal of benthic plastics from land sources withinthe ocean are possible. Here we investigated the hydrodynamic behavior(density, settling velocity and resuspension characteristics) of non-buoyantpreproduction plastic pellets in the laboratory. From these results we usedthe MOHID modelling system to predict what would be the likely transport anddeposition pathways of such material in the Nazaré Canyon (Portugal)during the spring/summer months of 2009 and the autumn/winter months of2011.

Model outputs indicated that non-buoyant plastic pellets would likely betransported up and down canyon as a function of tidal forces, with only aminor net down canyon movement resulting from tidal action. The modelindicated that transport down canyon was likely greater during theautumn/winter, primarily as a result of occasional mass transport eventsrelated to storm activity and internal wave action. Transport rates withinthe canyon were not predicted to be regular throughout the canyon system,with stretches of the upper canyon acting more as locations of pelletdeposition than conduits of pellet transport. Topography and the depths ofinternal wave action are hypothesized to contribute to this lack ofhomogeneity in predicted transport.

[学科分类] 地球化学与岩石