The role of ocean turbulence on the vertical motion of biofouled microplastic particles in a marine environment

This research investigates the influence of turbulence on the sinking of biofouled microplastic particles in the ocean. Marine plastic pollution has been identified as a global environmental crisis with over 8 million metric tons of plastic entering the ocean every year causing extensive damage to aquatic fauna and flora. Plastic particles smaller than 5 mm in size are categorized as microplastics. Buoyant microplastic particles travel deeper into the ocean due to the increase in density caused by the growth of a biofilm. Biofouling has been recently implemented in oceanographic computational models that attempt to track the spatial and temporal evolution of microplastic particles. Turbulence plays a crucial role in such models and the present study highlights the strong interactions between turbulence and the biofouling process. Our results show that polyethylene plastic particles with sizes in the micrometer range act similarly to Lagrangian tracers following the flow trajectories. On the opposite side, particles with sizes in the millimeter range oscillate in the upper ocean water column. Our ongoing research shows that the final particle tracking model and results would provide crucial insight into the fate of plastic particles in the ocean.