Microplastic retention due to gravel obstacles in combined wave

Current flows

Authored by

Remziye İlayda Tan Kesgin, Giovanni Passalacqua, Stefan Carstensen, Claudio Iuppa, Carla Faraci, Bjarke Eltard Larsen, Nils B. Kerpen, David R. Fuhrman

Abstract

This paper presents experiments involving microplastic (MP) transport and retention by marine obstacles such as gravel in (non-breaking) irregular waves combined with currents. Seven different non-buoyant MP groups having different shapes, dimensions and relative densities in the range 1.06 - 1.36 are considered, both in the presence and absence of gravel patches having different coverage densities and lengths. The results show that the retention and transport behavior of MP particles are significantly influenced by both particle Dean number and shape. Particles with higher Dean numbers (i.e. lower settling velocities) have higher mobility and lower retention tendency. Moreover, increasing the gravel obstacle coverage density and length substantially enhances MP retention efficiency, particularly for particles with lower Dean numbers. In wave±current conditions, the retention efficiency was generally reduced compared to pure wave scenarios. In addition, extended gravel patches with high density effectively retained most particle groups. These findings emphasize the role of benthic structures in influencing MP accumulation and suggest that small-scale marine obstacles can act as significant MP sinks under certain hydrodynamic conditions.

Details

Organisation(s)
Ludwig-Franzius-Institute of Hydraulics, Estuarine and Coastal Engineering
External Organisation(s)
Fatih Sultan Mehmet Vakıf University
University of Messina
Technical University of Denmark
Type
Article
Journal
Continental shelf research
Volume
301
No. of pages
17
ISSN
0278-4343
Publication date
11.06.2026
Publication status
E-pub ahead of print
Peer reviewed
Yes
ASJC Scopus subject areas
Oceanography, Aquatic Science, Geology
Sustainable Development Goals
SDG 14 - Life Below Water
Electronic version(s)
https://doi.org/10.1016/j.csr.2026.105721 (Access: Closed )