The methane concentration and stable carbon isotopic signature of methane were measured in different Arctic sea ice types as well as in seawater underneath the ice floe during the Polarstern expedition PS106.1. The ice drift took place between 4 - 15 June 2017, north of Svalbard (Macke and Flores, 2018). Sea ice cores were collected using a Kovacs Mark II 9cm drill ice corer. In all ice stations, the first ice core was used for in situ ice temperature measurements, and the second one for methane concentration, stable carbon isotopic signature of methane, bulk ice salinity and nutrient concentrations (Verdugo et al., 2021). Seawater samples were collected using a shipboard Sea-Bird Scientific SBE 911plus CTD (conductivity–temperature– depth) profiler equipped with ancillary sensors and integrated with a SBE32 CarouselWater Sampler with 24 Niskin bottles of 12L each (Macke and Flores, 2018).