Passive buoyant tracers in the ocean surface boundary layer: 2. Observations and simulations of microplastic marine debris

Brunner, Kelsey; Kukulka, Tobias; Proskurowski, G.; Law, Kara Lavender

doi:10.1002/2015jc010840

Cited by 69 publications

(65 citation statements)

References 50 publications

(74 reference statements)

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“…Adjusting each observation forward in time to a common sampling year of 2014 and to no-wind sampling conditions increased the observed plastic concentrations in nearly all samples ( figure S2). Previous studies have taken vertical wind-mixing of buoyant plastic debris into account by employing a simple one-dimensional model (Kukulka et al 2012) whose dynamics capture only a fraction of deep mixing observed (Brunner et al 2015). Certainly the variation in data collection (e.g., net mesh size); sample analysis (e.g., visual versus microscope identification); count-to-mass conversions (which are strongly dependent on particle size); and model design (e.g., source functions and removal processes) also contribute to the discrepancies.…”

Section: Discussionmentioning

confidence: 99%

A global inventory of small floating plastic debris

Sebille

Wilcox

Lebreton

et al. 2015

Environ. Res. Lett.

1,276

796

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Microplastic debris floating at the ocean surface can harm marine life. Understanding the severity of this harm requires knowledge of plastic abundance and distributions. Dozens of expeditions measuring microplastics have been carried out since the 1970s, but they have primarily focused on the North Atlantic and North Pacific accumulation zones, with much sparser coverage elsewhere. Here, we use the largest dataset of microplastic measurements assembled to date to assess the confidence we can have in global estimates of microplastic abundance and mass. We use a rigorous statistical framework to standardize a global dataset of plastic marine debris measured using surface-trawling plankton nets and coupled this with three different ocean circulation models to spatially interpolate the observations. Our estimates show that the accumulated number of microplastic particles in 2014 ranges from 15 to 51 trillion particles, weighing between 93 and 236 thousand metric tons, which is only approximately 1% of global plastic waste estimated to enter the ocean in the year 2010. These estimates are larger than previous global estimates, but vary widely because the scarcity of data in most of the world ocean, differences in model formulations, and fundamental knowledge gaps in the sources, transformations and fates of microplastics in the ocean.

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Section: Discussionmentioning

confidence: 99%

A global inventory of small floating plastic debris

Sebille

Wilcox

Lebreton

et al. 2015

Environ. Res. Lett.

1,276

796

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“…It is unclear how plastics relate to the drifters. Depending on their rising velocity, and wind and wave conditions (Brunner et al, ; Kukulka & Brunner, ; Kukulka et al, ), plastics drift both on the sea surface and submerged in the upper ocean (Kooi et al, ; Reisser et al, ). As a result, both types of drifters are possible valid proxies.…”

Section: Discussionmentioning

confidence: 99%

Role of Indian Ocean Dynamics on Accumulation of Buoyant Debris

2019

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Buoyant marine plastic debris has become a serious problem affecting the marine environment. To fully understand the impact of this problem, it is important to understand the dynamics of buoyant debris in the ocean. Buoyant debris accumulates in “garbage patches” in each of the subtropical ocean basins because of Ekman convergence and associated downwelling at subtropical latitudes. However, the precise dynamics of the garbage patches are not well understood. This is especially true in the southern Indian Ocean (SIO), where observations are inconclusive about the existence and numerical models predict inconsistent locations of the SIO garbage patch. In addition, the oceanic and atmospheric dynamics in the SIO are very different from those in the other oceans. The aim of this paper is to determine the dynamics of the SIO garbage patch at different depths and under different transport mechanisms such as ocean surface currents, Stokes drift, and direct wind forcing. To achieve this, we use two types of ocean surface drifters as a proxy for buoyant debris. We derive transport matrices from observed drifter locations and simulate the global accumulation of buoyant debris. Our results indicate that the accumulation of buoyant debris in the SIO is much more sensitive to different transport mechanisms than in the other ocean basins. We relate this sensitivity to the unique oceanic and atmospheric dynamics of the SIO.

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“…Kukulka et al () showed that large‐scale velocity structures observed in shallow water via acoustic Doppler profiler were also reproduced by LES. Brunner et al () compared profiles of microplastic debris with observations presented by Law et al (). Chen et al () compared horizontal diffusivities obtained from LES with observations from several studies (Lawrence et al, ; Murthy, ; Okubo, ), as shown later in Figure .…”

Section: Applications Of Les To Oml Turbulence Without Materials Transmentioning

confidence: 99%

Material Transport in the Ocean Mixed Layer: Recent Developments Enabled by Large Eddy Simulations

Chamecki

Chor

Yang

et al. 2019

Reviews of Geophysics

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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...

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Passive buoyant tracers in the ocean surface boundary layer: 2. Observations and simulations of microplastic marine debris

Cited by 69 publications

References 50 publications

A global inventory of small floating plastic debris

A global inventory of small floating plastic debris

Role of Indian Ocean Dynamics on Accumulation of Buoyant Debris

Material Transport in the Ocean Mixed Layer: Recent Developments Enabled by Large Eddy Simulations

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