Author(s): Vasilis Bellos; Pablo Valles; Mario Morales-Hernandez
Linked Author(s): Vasilis Bellos
Keywords: Lagrangian particle-tracking; Microplastics; Numerical simulation; Sensitivity analysis; Shallow water
Abstract: Microplastic transport in aquatic environments is governed by complex processes that remain poorly constrained. Among them, degradation, biofouling, and settling velocity play key roles in determining particle fate and distribution, yet their parameterization is highly uncertain due to the variability of particle properties and environmental conditions. This study performs a Global Sensitivity Analysis (GSA) to quantify the influence of these processes, and specifically the parameters involved for the assessment of settling velocity, to the microplastic trajectories. A Lagrangian transport model coupled to Eulerian shallow water hydrodynamics within the SERGHEI framework is used to simulate multiple scenarios varying particle density, size, degradation rate, and biofouling dynamics. For the GSA, the well-known Morris method is used. Results highlight the relative importance and interactions of these mechanisms, showing that process uncertainty can lead to significant differences in transport outcomes.
Year: 2026