[M-IS02] Ocean plastics, an earth science perspective

[MIS02-P07] A preliminary experiment of floating microplastic tracking model with a feedback to skin-layer temperature distribution

*Ryodai Kawano¹, Atsuhiko Isobe² (1.The Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 2.Research Institute for Applied Mechanics, Kyushu University)

Keywords:Microplastics, Skin layer, Seawater temperature distribution, Feedback

The potential for microplastics (MPs) to affect marine ecosystems has long been recognized, but their impact on the heat budget of the ocean skin layer remains insufficiently studied. In this study, we analyze the possibility that the presence of MPs alters the overall albedo, inhibiting surface warming and leading to localized cooling of the seawater. Furthermore, we investigate the potential for a feedback mechanism related to temperature gradients. Numerical simulations using a particle tracking model revealed that the distribution of MPs induces localized surface cooling, and that the resulting temperature gradient generates a pressure difference, leading to the formation of convergent flows. Additionally, it was suggested that the accumulation of MPs in these convergence zones could further enhance the cooling effect, reinforcing the feedback loop. These results indicate that MP dynamics are not merely subject to passive transport by ocean currents but may also be influenced by thermodynamic processes at the skin layer.