Microplastic Distribution and Transport Mechanisms in the South Sea and East China Sea of Korea

Microplastic distribution off the coast of Korea was investigated by collecting and analyzing surface seawater and sediment samples from the South Sea and East China Sea during the summer. Microplastic abundance was found to be highest in the YE area, followed by the EC area and the SS area in both seawater and sediment matrices. The dominant microplastic shapes and sizes were fragments and small particles (0.02-0.3 mm), respectively. This distribution pattern is explained by the transport of low-density, small-sized microplastics from other seas via the high salinity Taiwan Warm Current and Tsushima Warm Current flowing northward from the southern waters of the study area. In contrast, microplastics originating from the Korean landmass along the southern coast were less abundant, likely due to their dispersal by the strong currents of the Jeju Warm Current, Taiwan Warm Current, and Tsushima Warm Current, which carry microplastics toward the Korean Strait. This study highlights the critical role of prevailing ocean currents in shaping the spatial distribution of microplastics, providing insight into sources and transport mechanisms relevant for regional marine pollution management in the Korean coastal waters.