Microplastics patch based on hydrodynamic modeling in the north Indramayu, Java sea

Marine debris becomes a global issue due to its impact to ecosystem, human life, and marine environment. Microplastic is one of the marine debris types that need further attention due to its long term effect in marine life. The aim of the study was to investigate the microplastic transport in Java Sea, Indramayu for seven months period. The result showed that the tidal reversing current was dominant in Java Sea, with average current speed 0.04 – 0.32 m/s. The type of tidal movement in North Indramayu, Java Sea is mixed tide prevailing semidiurnal. The transport of microplastic has a circular-reversing pattern due to influences from the currents and waves. According to the result of this study, the start point of microplastics could be estimated ranges in distance 0.9 – 5.4 km from the location where they were sampled seven months later. Microplastic that currently resides in Java Sea allegedly came from South China Sea and Pacific Ocean. The result also indicates that Java Sea has a high probability to become the largest microplastic patch in Indonesia due to its reversing current, which can trap those particles for a long time (7 months microplastics mileage range of 1258.90 km – 1399.88 km), whether they originate from other ocean region or from Indonesia itself.