IMIS

This dataset contains ATR-FTIR spectra of five plastic polymer types (PE, PET, PP, PS and PVC) sized 500 - 1,000 µm in their pristine form, and ATR-FTIR spectra of the same particles following surface water-/deep-sea water-weathering in the natural environment, for a duration of 12 months under semi-controlled conditions. To do so, a mix of the microplastic fragments were filled into stainless steel tubes, which were placed in stainless steel containers. The containers were deployed in subsurface, coastal waters in the Norwegian Sea (Tromsø, Norway; 69.642730, 18.950389) in February 2021 and in deep-sea waters (2380 m depth) of the Mediterranean Sea (off the coast of Marseille, France; 42.807683, 6.043867) in April 2021, respectively. During the exposure at sea, the stainless-steel containers deployed in subsurface waters were manually cleaned at regular intervals to remove bivalves and other attached organisms. After retrieval, the stainless steel tubes were left under a fume hood to dry, after which microplastic particles were transferred into burnt (450 °C, 6 h) glass vials and stored for further use. Multiple weathered particles per polymer type were analysed.