The effect of wind mixing on the vertical distribution of buoyant plastic debris

TLDR

Micro‑plastic debris is widespread in subtropical gyres and is a major open ocean pollutant, yet its fate and transport are governed by poorly understood geophysical processes such as surface boundary layer mixing. The study aims to adopt a geophysical approach to accurately quantify and manage marine plastic pollution. Observations and a column model show that wind‑driven mixing vertically distributes plastic debris in the upper water column, indicating that surface measurements underestimate total oceanic plastic concentrations and existing datasets need reinterpretation.

Abstract

Micro‐plastic marine debris is widely distributed in vast regions of the subtropical gyres and has emerged as a major open ocean pollutant. The fate and transport of plastic marine debris is governed by poorly understood geophysical processes, such as ocean mixing within the surface boundary layer. Based on profile observations and a one‐dimensional column model, we demonstrate that plastic debris is vertically distributed within the upper water column due to wind‐driven mixing. These results suggest that total oceanic plastics concentrations are significantly underestimated by traditional surface measurements, requiring a reinterpretation of existing plastic marine debris data sets. A geophysical approach must be taken in order to properly quantify and manage this form of marine pollution.