[M-IS20] Ocean Plastics, an earth science perspective

[MIS20-04] Numerical model approach of macroplastic transport to find microplastic sources around the Indonesian archipelago

*Ryohei Kono¹, Atsuhiko Isobe¹ (1.Research Institute for Applied Mechanics, Kyushu University)

Keywords:Microplastic, Particle tracking model, Numerical simulation

Accordingly to the increase of plastic materials' demand around the world, the amount of plastic garbage has been correspondingly enlarging. This plastic garbage is degraded and thereafter fragmentized to microplastics with size <5mm under the natural conditions such as ultra-violet radiation and waves. However, the areas where microplastics intensely generate are still undiscovered. Additionally, there is a concern that the absorption of toxic substances on microplastic surface is potentially harmful to living marine organisms after ingestion. Therefore, it is urgent to understand how macroplastics from the land sources changes to microplastics in the ocean, and how microplastics thereafter move from these oceanic sources to the marine ecosystem.
In this study, using a particle tracking model, macroplastic releases were given to river mouths around the Asian seas. Thereafter the beaches on which these macroplastics were washed ashore were recognized as potential sources of microplastics under the assumption that the inflow of plastic garbage to the ocean is all converted into microplastics at these potential sources.