Water samples were taken during the Fram Strait expedition PS99.2 with RV Polarstern from 14 to 23 Jun 2016. Water samples were collected from the ship's seawater supply pumped through teflon tubing from about 11 m depth during underway as described in Liu et al (2018a). The same water samples were measured as in Liu et al. (2081b, 2018c). Water samples for CDOM absorption analysis were filtered through 0.2 µm filters and analysed onboard with a 2 m path length liquid waveguide capillary cell system (LWCC, WPI) following Levering et al. (2017). Details on method adaptation to our instrumentation set-up are provided in Alvarez et al. (2022). Salinity data were extracted from https://doi.pangaea.de/10.1594/PANGAEA.873153