Marine litter constitutes an environmental threat of growing concern around world oceans. Its spatial distribution is governed by different physical processes (including wind, waves and currents) characterized by a wide range of variability and complex interactions that result in aggregation and scatter of marine litter. In this context, LAgrangian transport of MARine litter and microplastics from modelling, analysis, and observations in CoAstal waters (LAMARCA) project aims to further understand the role of oceanic turbulence in marine litter (microplastics and meso/macrolitter) coastal aggregations, with special emphasis on scales from 1 m to 10 km, where the vertical motions play a relevant role. This project, which started in 2022, proposes an approach that combines ocean-current structures, oceanographic surveys, and new Lagrangian tools from complex systems to characterize marine connectivity and mixing properties in coastal waters. In April and October 2022, two 3-day multiplatform experiments were performed in the SE Bay of Biscay to study the aggregation of surface litter along frontal processes by means of the deployment of several clusters of surface drifters, high resolution transects with a towed ADCP, measurements of surface currents with an HF-radar, numerical simulations, and visual observations. We discuss preliminary results of dispersion properties and flow structure characterization obtained from different Lagrangian analysis diagnostics, including finite-size Lyapunov exponents and Lagrangian averaged divergence.

Primary Presenter: Anna Rubio, AZTI (arubio@azti.es)

Authors:

Anna Rubio, AZTI  (arubio@azti.es)

Ismael Hernandez-Carrasco, Institut Mediterrani d’Estudis Avançats (IMEDEA)   (ismaelhe@gmail.com)

Sloane Bertin, Université du Littoral - Côte d'Opale Laboratoire d'Océanologie et de Géosciences  (sloane.bertin@univ-littoral.fr)

Irene Ruiz, AZTI  (iruiz@azti.es)

Alexei Sentchev, Université du Littoral - Côte d'Opale Laboratoire d'Océanologie et de Géosciences  (alexei.sentchev@univ-littoral.fr)

Oihane Basurko, AZTI  (ocabezas@azti.es)

Alejandro Orfila, IMEDEA  (alejandro.orfila@csic.es)