JALON ROJAS, Isabel; LEMAIRE-COQUEUGNIOT, Adeline; GOMIT, Guillaume; ROMERO RAMIREZ, Alicia; JARNY, Sébastien

doi:10.5194/egusphere-egu24-20316

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JALON ROJAS, Isabel

Environnements et Paléoenvironnements OCéaniques [EPOC]

LEMAIRE-COQUEUGNIOT, Adeline
Environnements et Paléoenvironnements OCéaniques [EPOC]

GOMIT, Guillaume
Hydrodynamique et écoulements environnementaux [Institut Pprime] [HydEE]

Langue

Communication dans un congrès

Ce document a été publié dans

EGU General Assembly 2024, 2024-04-14, Vienna. 2024-03-11

Résumé en anglais

This study aims to elucidate the erodability behavior of microplastics in muddy environments like lakes, rivers, estuaries, and deltas, quantifying their critical shear stress on muddy sediment beds. Microplastics of diverse compositions, densities, shapes, and sizes were tested in a hydraulic flume with smooth and synthetic cohesive sediment beds. As flow intensity gradually increased, leading to particle mobilization, friction velocities and critical shear stresses were calculated. Initial results on smooth beds reveal that particle shape was a dominant factor in mobilization (sphere > pellet > fiber > sheet), followed by density: for equivalent shapes, denser particles required higher friction velocities for mobilization. Results from tests with different particle sizes and orientations relative to the flow highlight the influence of the exposed surface area: larger surface areas facilitate easier particle mobilization. Comparative experiments on smooth and muddy surfaces revealed higher shear stresses on cohesive sediment beds, attributed to particles sinking. Particle Image Velocimetry (P.I.V.) analysis showcased roughness-induced turbulence, marked by acceleration peaks and depressions, as the primary mechanism facilitating particle detachment from sediment.< Réduire

URI

https://oskar-bordeaux.fr/handle/20.500.12278/206061

DOI

http://dx.doi.org/10.5194/egusphere-egu24-20316

Project ANR

Processus physiques de transport de microplastiques en estuaires macrotidaux - ANR-22-CE01-0011

Unités de recherche

EPOC : Environnements et Paléoenvironnements Océaniques et Continentaux - UMR 5805