Patterns in dispersion and accumulation of plastic litter by ocean currents and eddies

Abstract:

Ocean currents and eddies carry floating plastic litter from coastlines into the infamous garbage patches in the centres of the gyres. However, the time scales and pathways on which this happens are unknown. In order to assess the impact of the plastic, it is key to know where it gets carried through vulnerable ecosystems.

In this talk, I will first discuss how tracks of satellite-tracked drifting buoys can be used to create a Markov model of dispersion at the surface of the ocean. I will show that this simple model accurately simulates the formation of the garbage patches, and can be used as a quick and easy tool to assess pathways of floating stuff.

I will then introduce more complicated models of passive particulates in the ocean, based on a Lagrangian description of the flow field from high-resolution models. While Lagrangian particle tracking is widely used in oceanography to track tracers, here the challenge is to make the virtual particles actually ‘behave’ like plastic.