Marine Litter Vital Graphics

GEOGRAPHICAL DISTRIBUTION

My litter your problem, your litter my problem

Discarded plastic moving around the ocean – on the surface, in the water column and on the sea floor – sometimes comes to rest. The geographical distribution of marine plastic debris is strongly influenced by the entry points and the different transport pathways, which are in turn determined by the density of plastic debris coupled with prevailing currents, wind and waves (Rech et al., 2014).

of most plastic, means it can drift around the ocean for a long time, becoming a true transboundary pollution problem.

Debris found in a location at any moment in time will be a mixture of locally-derived material plus particles that have been transported by current, wind or wave. More than half of the plastic that gets into the marine environment is less dense than seawater, so until it acquires some ballast (often from the accumulation of organic particles or marine organisms), it floats. Once discarded, plastic can accumulate close to its point of entry into the ocean or it can move long distances, ending up in remote locations far away from its entry point. This, combined with the slow degradation rate

Surface dispersion Surface circulation in the ocean is dominated by five large circular currents, called gyres – the North Atlantic, South Atlantic, North Pacific, South Pacific and Indian Ocean gyres. The currents around these gyres are primarily driven by wind and are the major transport mechanism for the dispersal of floating plastic debris (Barnes et al., 2009).

Plastic currents A giant distribution system for marine plastics

North Atlantic gyre

North Paci c gyre

South Atlantic gyre

South Paci c gyre

Indian Ocean gyre

Sample points used in the model

Microplastic concentration* Kilograms per square kilometre

0

10

Surface current

Source: Van Sebille, E., et al., A global inventory of small oating plastic debris, IOP Publishing, 2015; Cooperative Institute for Meteorological Satellite Studies

Marine Litter Vital Graphics

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