Microplastics in Surface Waters of the Gulf of Gdańsk and Baltic Sea, autumn 2019 - the dataset

Plastic pollution in the marine environment remains a pressing environmental concern. This study presents microplastic data collected during a research cruise aboard RV Oceania between 19 and 22 October 2019 in the Gulf of Gdańsk and the central Baltic Sea. Surface water sampling was conducted using a HydroBios net (product no. 438 214) with an effective mouth area of 70 × 20 cm, towed at 1.5–2.0 knots for 5–15 minutes per trawl. Post-sampling, the collected material was transferred to glass jars and frozen until analysis. In the laboratory, samples were thawed, pre-cleaned, digested using hydrogen peroxide, and re-concentrated on a 32 µm sieve. Microplastics were visually identified using a Leica M205C stereomicroscope and categorized by color and shape. Fiber dimensions were measured using Fiji software. Polymer identification was carried out via FTIR spectroscopy in the 4000–550 cm¹ range using a PerkinElmer Frontier spectrometer in ATR mode. The dataset provides insight into microplastic contamination in the southern Baltic Sea and contributes to ongoing assessments of marine plastic pollution.

The dataset consists of:
1. Description.pdf - detailed description of the dataset.
2. Metadata.csv: Metadata of sampling stations. Distance is a function of time towing time × speed, volume filtered is a function of distance × net sampling area.
3. Morphometric.csv: Morphometric measurements of microplastics identified in the samples.
4. Summary.csv: Summary data representing an abundance of each type and color of microplastics in a cubic meter of water.
5. plastics_baltic: folder with the photography collection of sampled microplastics.