Oceanographic conditions during Manta trawls in the South Atlantic Ocean with Bark Europa in autumn 2023

Surface ocean microplastic samples were collected in the South Atlantic and analysed. Trawls were conducted onboard the Bark Europa, a traditional three-masted, square-rigged Barque while under sail. The data was collected in autumn 2023 over 10 trawl locations from Cape Town (South Africa) to Montevideo (Uruguay). Surface water samples were collected using a Manta trawl (mouth area: 40.5 cm², mesh size: 500 µm; cod end: 333 µm), towed three consecutive times for ~30 minutes at each station. Environmental conditions such as sea state, wind speed, and wind direction were recorded. Three samples were collected at each site, except for one location where only one trawl was conducted due to environmental conditions. This dataset describes these environmental conditions. The trawls were monitored and adjusted to ensure smooth sampling outside the vessel's wake zone. Microplastic samples collected during the study were processed using a series of stacked sieves (5 mm, 1mm, 0.3mm) and rinsed with filtered fresh water. Particles with largest dimension over 1 mm were visually identified (removed if not polymer), and everything smaller was collected. Samples were then chemically purified and investigated via stereoscopy , followed by ATR-FTIR spectroscopy in the laboratory to identify the polymer types of the microplastics. Cross-contamination was minimized through procedural blanks, samples of potential contamination and careful equipment handling. The microplastic particles collected were also categorized by shape (film, foam, fragment, line, microfiber, microbead, industrial pellet) and colour.