Modeling Plastic Dispersion in the NW Mediterranean: Lagrangian Analysis of Ebro & Arno Rivers
Ocean Sciences, Modeling
Research area
The scientific context of my project revolves around numerical oceanographic modeling and analysing the dynamics of plastic contaminants to understand their transport and dispersion mechanisms.
By integrating hydrodynamic models (such as ROMS) with Lagrangian tracking approaches, the project aims to elucidate the movement, accumulation, and degradation of plastic particles in aquatic environments, particularly in river systems and coastal regions of the Mediterranean.
Project goals
The objective of this work is to develop a high-resolution hydrodynamic modeling system coupled with a Lagrangian particle-tracking model to simulate trajectories and accumulation patterns arising from coastal, riverine, and shipping-related sources in the Mediterranean basin.
The study focuses on the representation and parameterization of key transport processes, including horizontal dynamics (advection, beaching, washing off) and vertical dynamics (sinking, biofouling, ingestion/egestion)
Computational approach
To obtain accurate results, several technological challenges must be addressed:
Model Coupling: Effectively coupling the hydrodynamic model (ROMS) with the Lagrangian model (LTRANS and GNOME) for precise tracking of plastic particles, ensuring realistic simulations.
Data Resolution and Accuracy: Acquiring high-resolution environmental data (e.g., current speeds, river discharge) is crucial, while addressing uncertainties in input data, such as river flow and plastic input.
Scalability and Computational Power: Running simulations with large datasets, especially when modeling multiple scenarios, requires significant computational resources for high-resolution models.
Model Validation: Aligning model outputs with real-world data, especially in complex systems like river deltas, to validate plastic concentrations.
Integration of Event-Driven Changes: Incorporating environmental variations (e.g., rainfall, seasonal changes) into the model, adjusting particle properties and scales as necessary.
Balancing computational efficiency, data quality, and model robustness is essential for accurate, actionable results in Mediterranean plastic pollution management.
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The figure illustrates the workflow of my research project, where modeling and sampling activities occur sequentially, while the development of the two models (using different Lagrangian approaches) progresses concurrently.
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The figure illustrates the workflow of my research project, where modeling and sampling activities occur sequentially, while the development of the two models (using different Lagrangian approaches) progresses concurrently.
Key results
The current stage of model development focuses on the implementation and simulation of key horizontal transport processes, including advection, beaching, and windage, which together govern the large-scale dispersion and redistribution of particles at the sea surface. Advection, driven by the underlying hydrodynamic fields, represents the primary mechanism controlling particle trajectories, while windage accounts for the direct influence of wind forcing on floating particles, enhancing their transport relative to surface currents. Beaching processes are also incorporated to simulate the interaction between particles and coastlines, allowing for the representation of stranding and temporary or permanent retention along shorelines. At this stage, vertical processes—such as sinking, biofouling, and ingestion/egestion—have not yet been implemented and will be addressed in subsequent phases of model development. These processes are expected to play a crucial role in modulating particle residence times, vertical distribution, and eventual fate within the water column. Their future integration will enable a more comprehensive and physically consistent representation of particle dynamics, ultimately improving the model’s capability to capture three-dimensional transport pathways and accumulation patterns in the marine environment.
Resource usage
Although access to the TeRABIT resources was granted for this project, they have not yet been actively used due to delays in the development and stabilization of the modeling framework. In particular, ongoing efforts have focused on refining the hydrodynamic–Lagrangian coupling and ensuring the robustness of the implemented horizontal transport processes (e.g., advection, windage, and beaching).
What's next
Usage of HPC resource to run a hydrodinamic (ROMS model) model with whole basin of Mediterranean Sea with 500 m horizontal resolution instead of using CMEMS fields (almost 4 km horizontal resolution)
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Modeling workflow and integration of improvements using TeRABIT resources, from coarse-resolution hydrodynamics to high-resolution, HPC-enabled simulations, enhancing particle transport and nearshore process representation
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The figure illustrates the workflow of my research project, where modeling and sampling activities occur sequentially, while the development of the two models (using different Lagrangian approaches) progresses concurrently.
Rebecca Agati
CNR - ISMAR; University of Florence; OGS
I have a Master's degree in environmental engineering and am certified as a Hydraulic Engineer. My background focuses on fluvial and environmental hydraulics. Both my bachelor's and master's theses were experimental studies on the transport of microparticles in aquatic and terrestrial environments. At the end of my master's, I spent 6 months in the Netherlands (Leiden) writing my thesis in collaboration with the University of Environmental Sciences, studying the trophic transfer of nanoplastics in a food chain. An article based on this research was published: Zantis, Laura J., et al. 'Quantitative tracking of nanoplastics along the food chain from lettuce (Lactuca sativa) to snails (Cantareus aspersus).' Science of the Total Environment 955 (2024): 176848. I am currently pursuing an international doctorate in civil and environmental engineering, focusing on a Plastic Budget Methodology to model plastic pathways, degradation, and storage in rivers, coastal areas, and open seas.