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Material transport in the ocean mixed layer (OML) is an important component of natural processes such as gas and nutrient exchanges. It is also important in the context of pollution (oil droplets, microplastics, etc.). Observational studies of small-scale three-dimensional turbulence in the OML are difficult, especially if one aims at a systematic coverage of relevant parameters and their effects, under controlled conditions. Numerical studies are also challenging due to the large-scale separation between the physical processes dominating transport in the horizontal and vertical directions. Despite this difficulty, the application of large eddy simulation (LES) to study OML turbulence and, more specifically, its effects on material transport has resulted in major advances in the field in recent years. In this paper we review the use of LES to study material transport within the OML and then summarize and synthesize the advances it has enabled in the past decade or so. In the first part we describe the LES technique and the most common approaches when applying it in OML material transport investigations. In the second part we review recent results on material transport obtained using LES and comment on implications. Plain Language SummaryThe transport of materials in the ocean is a topic that has been attracting much interest in the last decades. Much of the importance of this topic lies in the fact that many of the materials considered impact ecosystem health and/or ocean-related industries. As examples we have pollutants (such as plastic and oil spills) and other natural substances like nutrients and phytoplankton. We focus on the upper part of the ocean, which is heavily impacted by the interaction with the atmosphere and, as a result, is particularly difficult to understand and predict. However, using increasingly more powerful computers, scientists have made significant advances over recent years. As a result, a large amount of new research has been made by different research groups investigating different aspects of the problem. In this review, we compile, summarize, and synthesize results produced by computer simulations into a coherent framework with the goal of better understanding the state of art of material transport. Finally, we conclude the paper with open research questions and directions for future research.are capable of producing their own motion in response to different environmental stimuli (e.g., plankton swimming).This review paper consists of two main parts. Part 1 focuses on the LES technique, covering general modeling aspects and specific details relevant for its application to the OML. We focus on application of the technique to the filtered Navier-Stokes equations including relevant terms leading to, for example, the Craik-Leibovich (CL) equations. We discuss several different approaches to subgrid-scale (SGS) modeling that have been used by different groups. We also contrast the use of Eulerian and Lagrangian approaches to represent material transport and their respective advantages an...

We introduce a general framework to predict the fate of buoyant materials in the oceanic mixed layer. The framework is based on the estimation of a turbulence velocity scale for the vertical mixing of buoyant materials. By combining this velocity scale with the material's terminal rise velocity and a K‐profile parameterization, we are able to derive an analytical prediction for the vertical profile of material concentration that is shown to be a reasonably accurate and general representation for oceanic mixed layer regimes driven by various levels of wind shear, Stokes drift, and buoyancy flux. The analytically predicted profile allows us to estimate relevant parameters for the fate of buoyant materials, such as the depth of a plume's center of mass and the horizontal transport. We show that the predictions agree with large‐eddy simulations driven by various combinations of wind shear, Stokes drift, and buoyancy fluxes.