17:15 〜 18:45
[MIS09-P01] Current state of spatial distribution of microplastics in the Indian Ocean based on observations and a particle tracking model
キーワード：Marine Plastics, Particle Tracking Model, Indian Ocean, Microplastics
Large amounts of mismanaged plastic wastes enter the world`s oceans every year. Indian Ocean also receives a high amount of waste released from the countries bordering it coastlines. Previous study by Irfan et al. (2024) suggests the trapping of macroplastic debris in the Indian Ocean under the influence of wind and Stokes drift. However, microplastics being smaller in size travel in the subsurface layer, free from windage and Stokes drift, and so they may be free from the trapping. However, little is known about the transport and spatial distribution of microplastic debris in the Indian Ocean. Therefore, this research aims to understand the transport of microplastic debris in the Indian Ocean using a particle tracking model (PTM).
In PTM the macroplastic particles are input from river mouths based on Lebreton et al.(2017). The macroplastic particles break down into microplastic particles over the assigned timescale such that the microplastics are carried by ocean surface currents from HYCOM, horizontal diffusivity. The model incorporated an exchange process between ocean and beaches as well as the removal processes for the microplastic debris from the surface layer. The modeling starts in the ocean free of plastics and continued for many years during which the daily HyCOM currents were repeatedly used in the computation.
Through the PTM experiments we demonstrate that the microplastic particles, free from windage and Stokes drift at increasing depths may have a wider spatial distribution and may escape to other oceans unlike the macroplastics that are trapped in the Northern Indian Ocean.
In PTM the macroplastic particles are input from river mouths based on Lebreton et al.(2017). The macroplastic particles break down into microplastic particles over the assigned timescale such that the microplastics are carried by ocean surface currents from HYCOM, horizontal diffusivity. The model incorporated an exchange process between ocean and beaches as well as the removal processes for the microplastic debris from the surface layer. The modeling starts in the ocean free of plastics and continued for many years during which the daily HyCOM currents were repeatedly used in the computation.
Through the PTM experiments we demonstrate that the microplastic particles, free from windage and Stokes drift at increasing depths may have a wider spatial distribution and may escape to other oceans unlike the macroplastics that are trapped in the Northern Indian Ocean.