First expedition Jaywun research vessel: assessment of microplastics from international waters, Spain to Abu Dhabi, U.A.E

This study provides a transboundary evaluation of microplastic (MP) pollution across marine corridors primarily major shipping routes that link the Atlantic Ocean to the Arabian Gulf, navigating three of the most important choke points in international shipping – the Suez Canal, Bab-el-Mandeb, and the Strait of Hormuz as well as the Strait of Gibraltar. The research was conducted during the transfer voyage of the research vessel Jaywun from Spain to Abu Dhabi between November and December 2022. A total of 100 surface-water samples were collected from six major regions: the North Atlantic Ocean (Western Europe), Mediterranean Sea, Red Sea, Arabian Sea, Strait of Hormuz and UAE waters within the Arabian Gulf. MP concentrations (>500–5000 µm) varied widely, from 4 MPs L−1 in the Mediterranean to 290 MPs L−1 at the Western entrance to the Strait of Gibraltar, with an overall average of 34.7 ± 29.0 MPs L−1 across all sites. Regionally, the Arabian Sea recorded the highest mean concentrations (56.0 ± 31.6 MPs L−1), while lower values occurred in the Mediterranean (15.5 ± 9.6 MPs L−1 and Red Sea (24.5 ± 11.0 MPs L−1 UAE waters showed a moderate abundance (30.6 ± 21.4 MPs L−1 with localized hotspots near major ports and structured shipping routes. Polymer analyses revealed polyester (PES) and polyethylene terephthalate (PET) as dominant polymers (>57%), followed by polyamides (PA6/66), acrylonitrile butadiene styrene (ABS), with minor contributions from cellulose acetate (CA), polystyrene (PS), polypropylene (PP), and polyvinyl chloride (PVC), indicating inputs from textiles, packaging, fishing gear, and industrial sources. The Pollution Load Index (PLI) ranged from 1.00 to 8.51 (mean 2.85 ± 1.9). Furthermore, Kruskal–Wallis analysis revealed significant regional differences in microplastic concentrations (H = 20.93, p< 0.001), while Spearman correlation indicated no significant transect-wide trend (ρ = 0.033, p = 0.743). Spatial variability and polymer diversity underscore the influence of hydrodynamic transport and maritime activities on MP dispersion. This dataset provides an important baseline for large-scale monitoring of marine microplastics across interconnected oceans and serves as a valuable reference for comparative assessments within Abu Dhabi’s waters.