Challenging Issues in Microplastic Transport by Submarine Turbidity Currents

Abstract

Research on microplastic transport by turbidity currents remains in its infancy. Given the growing recognition of microplastic pollution as a significant environmental concern, it is imperative to investigate and understand this potentially dominant transport mechanism. By synthesizing current research challenges, we aim to outline key directions for future investigations. From the perspectives of in situ observations, physical modeling, and numerical simulations, there is a notable lack of mature or effective methods to fully understand the physical processes governing microplastic transport by turbidity currents. At this critical juncture, we propose that research priorities should focus on methodological development, encompassing: (i) Optimized redesign of sediment traps, (ii) development of microplastic transport models in both Newtonian and non-Newtonian fluids, (iii) establishment and simplification of interaction models among sediment, microplastic particles and ambient fluid, and (iv) application of machine learning algorithms in numerical model optimization. It merits attention that the fundamental principle underlying these research directions is the necessity to treat microplastics as true sediment particles, rather than as shapeless, non-deformable, or even massless and un-volumetric materials simply following the fluid motions.