MODELPlastics workshop - Modelling Ocean Plastic Litter in a Changing Climate: Gaps and future directions

doi:10.1016/j.marpolbul.2019.05.063

Marine Pollution Bulletin

Volume 146, September 2019, Pages 22-25

https://doi.org/10.1016/j.marpolbul.2019.05.063 Get rights and content

Highlights

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Multi-disciplinary approaches are needed to tackle plastic pollution.
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Data quantity and quality must be improved to develop accurate models.
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Models are crucial tools to predict cumulative impacts of multiple stressors.

Abstract

Here we summarize the overarching issues that emerged from a workshop held to discuss scientific challenges and future directions on the use of numerical models to predict the amount, distribution and effects of plastic pollution on marine ecosystems. The need for multi-disciplinary approaches, standardized protocols for plastic quantification and analyses, using realistic contaminant concentrations in laboratorial experiments and targeting early-life stages of marine organisms were pointed out as needs to improve data accuracy. Participants also enumerated a list of gaps that include, identification of indicator organisms of plastic contamination, selection of biomarkers and the role of extreme events on plastic dynamics. Responding to these gaps will contribute to improve data quantity and quality and, thus, allow developing more reliable models. A crucial role is foreseen for modelling tools as they can incorporate the cumulative impacts of multiple stressors, including the individual-level effects of plastics, to the population- and ecosystem level.

Section snippets

Acknowledgements

Authors acknowledge EuroMarine for funding through a Foresight Workshop EuroMarine 2017 call, participants in group discussions, CIIMAR (Portugal), MARE (Portugal), OGS (Italy), IEO (Spain) for institutional support. A.M.M.G. and F.B. acknowledge FCT- Foundation for Science and Technology (Portugal) through the strategic project UID/MAR/04292/2019 granted to MARE and the post-doctoral grants SFRH/BPD/97210/2013 (A.M.M.G.) and SFRH/BPD/99747/2014 (F.B.) co-funded by the Human Potential

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Cited by (7)

Plastic pollution in the aquatic ecosystem: An emerging threat and its mechanisms
2024, Advances in Chemical Pollution, Environmental Management and Protection
The smaller fragments of plastics including microplastics and nanoplastics are of particular concern since their existence throughout the food web is more persistent than larger particles. Microplastics enter in the food chain and its very bottom, when aquatic organisms eat or ingest contaminated food materials, and keep being transferred in the next food web predator, including humans. These are detected in Asia, Europe and North America and the studies show that aquatic organisms frequently ingest microplastics across a variety of feeding guilds. Marine organisms may cause shock, inner or outer injuries, ulcerating sores, blocking digestive tracts, fake feelings, degraded feeding capabilities, fatigue, weakness, limited predator prevention, or death in the ingestion of large plastic material and/or particles. However, effects of ingestion of microplastic particles on marine organisms and the toxicity mechanisms are largely unknown. There is much more limited evidence of the impacts of microplastic intake on freshwater species, both in the limited number of studies performed and the number of species examined. However, the few recent studies of freshwater suggest that physical effects are analogous to those carried out in the sea. Therefore, we reviewed the state of the science for briefly identifying knowledge gaps and investigating research needs. To date, a small number of studies have been conducted to investigate biological effects of plastics on aquatic species, and the significant transport pathways of plastics from freshwater ecosystems to marine ecosystems and vice-versa have received little attention. So potential sources and the fate of the environment continue to be investigated. Likewise, there is limited research to explain how plastics and its fragments could transfer from the freshwater to terrestrial and to marine ecosystems, and to know if they can affect human health.
Sources, sinks and transformations of plastics in our oceans: Review, management strategies and modelling
2023, Science of the Total Environment
Citation Excerpt :
In the same way, in an estuarine gradient, marine debris' transboundary was studied through hydrodynamic models, ground truthing estimates and regressive vector analysis (Krelling et al., 2017). In 2019, Martins et al. (2019) made predictions of quantity, distribution and plastic pollution effects on marine ecosystems in order to develop in a future a numerical model. Although numeric models and analysis, also help to definition of marine litter clean-up and mitigation strategies at an estuarine scale (Núñez et al., 2019).
Currently, 60–80 % of litter is plastic, and almost 10 % ends up in the ocean directly or indirectly. Plastics often suffer from photooxidation producing microplastics and these microplastics derived from the breakdown of larger plastics are called secondary microplastics. These compounds simply cannot be extracted from the oceans, and once mixed, they enter the food chain and may have toxic effects.
This work reviews the current existing information on the topic in the scientific literature. Then, the current plastic management strategies in the marine environment are analysed, with the objective of identifying possible needs and improvements from a sustainable point of view, and to define new approaches. Simultaneously, a material flows analysis in different media of the marine environment is carried out using system dynamics. A preliminary model of plastics mobilization into the ocean to other media of the marine environment (like sediments and biota) is developed and validated with the existing data from the previous steps of the work.
This work expands the current knowledge on the plastics management, their transformations and accumulation in the marine environment and the harmful effects on it. Likewise, preliminary dynamic model of mobilization of plastics in the ocean is implemented, run, and validated. The developed model can be used to predict trends in the distribution of the plastics in the ocean with time. In addition, the most important reservoirs of plastics in the ocean can be observed. Although plastics undergo transformations in the marine environment, it is not a means of disposal since most of them are non-biodegradable. Most plastics accumulate on the seabed. The proportion of microplastics found in sediments is higher than that of macroplastics.
Hydrodynamic modelling in marginal and coastal seas — The case of the Adriatic Sea as a permanent laboratory for numerical approach
2022, Ocean Modelling
Citation Excerpt :
An inverse modelling approach was recently proposed by Kaandorp et al. (2020) to close the mass balance of marine litter in the Mediterranean sea and to estimate the amount of marine litter in the water column, seafloor and beaches. Martins et al. (2019) concluded the 2018 Model Plastic workshop underlying three main gaps in the marine litter modelling: (1) the water–sediment plastic interaction process, (2) the quantification of point and diffuse sources of plastic, and (3) the identification of hot spots of plastic accumulation. In this context, an advantage of the Lagrangian approach is that back-propagation simulations (advection of particles backwards in time) can be used to investigate where the marine litter at a certain location come from Liubartseva et al. (2016) and Ličer et al. (2020).
Understanding the water circulation in oceans and coastal seas is among the key topics of oceanographic and climate research. Hydrodynamic studies form the basis for many oceanographic subjects, whether sediment transport, morphology, water quality, ecological and climate changes are being investigated. Hydrodynamic modelling of oceans and coastal seas has become a fundamental tool for describing the dynamics of marine environments, revealing the human impact on the sea and promoting sustainable development of marine resources. By complementing – through data assimilation – more and more diffuse and integrated global and regional observing systems (composed of coastal gauges, moorings, buoys, satellites, drifters), hydrodynamic models provide a deterministic 4D view of the ocean state. In this context, the semi-enclosed Adriatic Sea represents a natural long-standing laboratory for hydrodynamic modelling. The peculiar historical, morphological and oceanographic characteristics of this basin and its complex coastline stimulated over decades the development and application of several ocean and coastal models. In this work, we review different aspects of hydrodynamic modelling covered by the literature, highlighting the wide variety of model applications carried out in the Adriatic Sea which could serve as examples for semi-enclosed, marginal and coastal seas worldwide. Within the scope of the review, we find that although significant progress has been made over the last few decades, most of the modelling studies underrate the importance of a detailed representation of the land-coastal-sea fluxes. We list a set of recommendations that can be used as guidelines for model implementation to broaden the applicability of hydrodynamic models in future studies. Finally, we discuss the remaining questions that still need to be further explored.
Marine litter and climate change: Inextricably connected threats to the world's oceans
2022, Science of the Total Environment
Citation Excerpt :
There are growing concerns that the interaction between marine plastic pollution and climate change can significantly impact marine biodiversity, and that this impact is set to accelerate and worsen worldwide over the coming years and decades, conflagrating to diminish the adapting capacity of the world's oceans (Good et al., 2020; STAP, 2011). There are many important knowledge gaps in the interaction of climate change and other local stressors, including marine litter, which are likely context-dependent, and the resulting combined impact may be different at a species level compared to the trophic or ecosystem level (Gissi et al., 2021; Martins et al., 2019). In the case of seabirds in particular, experts are calling for special attention to this synergism between plastic debris and climate change in order to guide management actions, especially as bird distributions shift raising the question of how a changing climate may influence the interaction of seabirds with plastics (Good et al., 2020).
The global issues of climate change and marine litter are interlinked and understanding these connections is key to managing their combined risks to marine biodiversity and ultimately society. For example, fossil fuel-based plastics cause direct emissions of greenhouse gases and therefore are an important contributing factor to climate change, while other impacts of plastics can manifest as alterations in key species and habitats in coastal and marine environments. Marine litter is acknowledged as a threat multiplier that acts with other stressors such as climate change to cause far greater damage than if they occurred in isolation. On the other hand, while climate change can lead to increased inputs of litter into the marine environment, the presence of marine litter can also undermine the climate resilience of marine ecosystems. There is increasing evidence that that climate change and marine litter are inextricably linked, although these interactions and the resulting effects vary widely across oceanic regions and depend on the particular characteristics of specific marine environments. Ecosystem resilience approaches, that integrate climate change with other local stressors, offer a suitable framework to incorporate the consideration of marine litter where that is deemed to be a risk, and to steer, coordinate and prioritise research and monitoring, as well as management, policy, planning and action to effectively tackle the combined risks and impacts from climate change and marine litter.
The Bay of Biscay as a trapping zone for exogenous plastics of different sizes
2020, Journal of Sea Research
Citation Excerpt :
Therefore, the so-called medium and high windage items (Duhec et al., 2015) will be advected by the combination of both factors: ocean currents and wind. Development and use of oceanographic models have been identified among the research priorities to support the monitoring programs of marine litter (Martins et al., 2019). Modelling of oceanographic currents can help to enable backtracking transportation schemes and sources, average drift times and identify accumulation areas (see e.g. Maximenko et al., 2012).
The near-surface transport of exogenous plastics that enter the Bay of Biscay near Cape Ortegal (NW Spain), the main coastal entrance of marine litter into this semi-enclosed sea, were analyzed using a particle tracking model over the period 2009–2018. Four wind drag coefficients were considered to account for the different windages due to the diverse sizes of marine litter. The combined effect of winds and currents results in a higher concentration of floating plastics nearshore favoring beaching. On the other hand, the movement of the smallest plastics (< 5 mm) is only due to the effect of currents which favors their oceanward spread, hindering their further recovery.
Observations and idealized modelling of microplastic transport in estuaries: The exemplary case of an upwelling system (Ría de Vigo, NW Spain)
2020, Marine Chemistry
Citation Excerpt :
Complex numerical models, which are routinely applied to study hydrodynamic and transport processes, could represent a reasonable complementary approach to idealized models to study and predict MPs accumulation in estuaries. Nevertheless, the application of this type of models for plastic pollution in these environments is still in its infancy, and there are also many challenges to solve associated with their application (e.g. Martins et al., 2019; Jalón-Rojas et al., 2019). In spite of the simplifications noted above, the model used in this work was able to reproduce the main features of the observed MP distribution, to estimate the relative influence of the different forcing factors, and to identify the trapping conditions of MPs, both at the bottom and near the surface.
Microplastics (MPs) pollution in marine environments has received considerable attention over the past two decades due to the increased awareness of its potential risks to ecosystems. Numerical simulations can be used to provide estimates of MPs fate and distribution, but so far this approach has been largely applied to the open ocean. In this work, the distribution patterns of MPs in a prototype coastal upwelling environment (Ría de Vigo estuary, Spain) is investigated using a combined approach of field data and modelling. Water and sediment samples were collected at different locations along the Ría during both upwelling and downwelling conditions. Experiments using an idealized 2D-vertical model were conducted to explain the observed MP distribution and elucidate the relative importance of river discharge, wind-driven and density-driven circulation. Microplastics were found at all stations in all samples. The largest observed fraction of MPs corresponded to fibres followed by plastic paint sheets and fragments. The trapping or flushing of MPs was mainly controlled by the wind forcing, whose effects on the circulation normally exceeds those of the density-driven and river flows. During upwelling conditions, more MP items were collected near the surface at the outer half of the estuary than during downwelling. The seaward near-surface circulation induced by the wind and density gradient jointly contributed to flushing out floating MPs. Near the bottom, the landward wind-induced and gravitational circulation formed estuarine MP maxima (EMPM) inside the estuary. Pellets, fragments, and films were more efficiently trapped than fibres, as their EMPM were located more upstream. The results suggested that downwelling-favourable winds caused an overall landward (seaward) displacement of the distribution of floating (sinking) MPs. Modelling results indicate that winds dominate the circulation in the outer part of the estuary, whereas near the head the gravitational circulation takes over the control of the net flow. The particular location of the EMPM appears to be controlled by the competition of density-driven and wind-driven flows.

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Marine Pollution Bulletin

Highlights

Abstract

Section snippets

Acknowledgements

References (22)

Relative importance of microplastics as a pathway for the transfer of hydrophobic organic chemicals to marine life

Environ. Pollut.

Studies of the effects of microplastics on aquatic organisms: what do we know and where should we focus our efforts in the future?

Sci. Total Environ.

The present and future of microplastic pollution in the marine environment

Environ. Pollut.

Tracking plastics in the Mediterranean: 2D Lagrangian model

Mar. Pollut. Bull.

Restoring fish ecological quality in estuaries: implication of interactive and cumulative effects among anthropogenic stressors

Sci. Total Environ.

Do microplastics affect marine ecosystem productivity?

Mar. Pollut. Bull.

Microplastics in the marine environment

Mar. Pollut. Bull.

Microplastics in the aquatic environment: evidence for or against adverse impacts and major knowledge gaps

Environ. Toxicol. Chem.

The impact of polystyrene microplastics on feeding, function and fecundity in the marine copepod Calanus helgolandicus

Environ. Sci. Technol.

Plastic accumulation in the Mediterranean Sea

PLoSOne

Lessons in modelling and management of marine ecosystems: the Atlantis experience

Fish Fish.

Cited by (7)

Plastic pollution in the aquatic ecosystem: An emerging threat and its mechanisms

Sources, sinks and transformations of plastics in our oceans: Review, management strategies and modelling

Hydrodynamic modelling in marginal and coastal seas — The case of the Adriatic Sea as a permanent laboratory for numerical approach

Marine litter and climate change: Inextricably connected threats to the world's oceans

The Bay of Biscay as a trapping zone for exogenous plastics of different sizes

Observations and idealized modelling of microplastic transport in estuaries: The exemplary case of an upwelling system (Ría de Vigo, NW Spain)

ViewpointMODELPlastics workshop - Modelling Ocean Plastic Litter in a Changing Climate: Gaps and future directions

Highlights

Abstract

Section snippets

Acknowledgements

Environ. Pollut.

Sci. Total Environ.

Environ. Pollut.

Mar. Pollut. Bull.

Sci. Total Environ.

Mar. Pollut. Bull.

Microplastics in the marine environment

Mar. Pollut. Bull.

Microplastics in the aquatic environment: evidence for or against adverse impacts and major knowledge gaps

Environ. Toxicol. Chem.

The impact of polystyrene microplastics on feeding, function and fecundity in the marine copepod Calanus helgolandicus

Environ. Sci. Technol.

Plastic accumulation in the Mediterranean Sea

PLoSOne

Lessons in modelling and management of marine ecosystems: the Atlantis experience

Fish Fish.

Viewpoint
MODELPlastics workshop - Modelling Ocean Plastic Litter in a Changing Climate: Gaps and future directions