LDIR Data: Microplastic fluxes transported by multiple turbidity currents to the deep sea

This dataset contains the raw Laser Direct Infrared (LDIR) imaging data underlying the manuscript “First quantification of deep-sea microplastic fluxes transported by multiple turbidity currents in the submarine Congo Canyon” (Pohl, Hildebrandt, Eggenhuisen, Baker, Talling, Proefrock, Simmons, Silva Jacinto, Hage & Dennielou). The samples are eight composite sediment samples (ST-1 to ST-8) and two procedural blanks. The sediment came from a sediment trap on mooring M9 in the Congo Submarine Canyon, deployed 30 m above the canyon floor at 2,172 m water depth from September 2019 to January 2020 (RRS James Cook cruise JC187). Microplastics were extracted by two ZnCl₂ density separations (1.7 g/cm³) combined with microwave-assisted oxidative and enzymatic matrix digestion. They were then analysed on silver-coated slides with an Agilent 8700 LDIR Chemical Imaging System over a particle size range of 10 - 1000 µm. There is one Excel file per sample or blank, each with the following sheets: Info: sample and measurement metadata. Polymerclasses: how spectral library entries were assigned to polymer clusters. LDIR_Raw_data: all detected particles, with morphological parameters (width, height, diameter, aspect ratio, area, perimeter, eccentricity, circularity, solidity), the best library match, the hit quality index (HQI) and a validity flag. Particles: only the particles that passed the identification criterion (HQI ≥ 0.85). Evaluation: particle counts per polymer cluster and size class (10–50, 50–100, 100–200, 200–500, >500 µm).