Identifying plastic accumulation zones in coastal seas: The Roatan Island case study

Area of Science:

• Oceanography
• Environmental Science
• Fluid Dynamics

Background:

• Marine plastic pollution is a significant global environmental concern.
• Floating plastic debris can form large accumulations, impacting ecosystems.
• Understanding the dynamics of these accumulations is crucial for effective management.

Purpose of the Study:

• To investigate the effectiveness of Lyapunov Exponents as a diagnostic tool for characterizing marine plastic accumulations.
• To assess the ability of Lyapunov Exponents to capture the transient nature of plastic debris in coastal seas.

Main Methods:

• Utilized weather and ocean model data as input for a Lagrangian drift model.
• Computed Lyapunov exponents from the drift simulation outputs.
• Conducted sensitivity studies by varying parameters like separation ratio, wind coefficient, start date, and simulation duration.

Main Results:

• Lyapunov Exponents, when properly configured, can effectively highlight areas of plastic accumulation.
• The study confirmed the transient nature of these plastic accumulations in coastal environments.
• Sensitivity analyses provided insights into the optimal settings for using Lyapunov Exponents.

Conclusions:

• Lyapunov Exponents are a valuable tool for identifying and characterizing marine plastic hotspots.
• This method offers a novel approach to understanding the dynamics of plastic pollution in coastal waters.
• The findings support the use of Lagrangian Coherent Structures diagnostics for environmental monitoring.