Station Nord

Here we report how inputs of meteoric water affect the physical and biogeochemical properties of both the water column and sea ice cover on the Wandel Sea shelf, northeastern Greenland, during spring 2015. Depleted 18O observed in the water column, with surface water as low as –16.3 ‰, suggest a strong input of meteoric water (i.e., water derived from precipitation). Depleted 18O observed within sea ice (from –21.5 to –8.0 ‰) reflect its formation from already depleted surface water. In addition, the thick snow cover present during the survey promotes the formation of snow ice as well as insulates the ice cover. Within sea ice, the relatively warm temperature and low salinity impeded impedes ikaite formation. However, measurements of total dissolved inorganic carbon and total alkalinity indicate the dissolution of calcium carbonate as the main process affecting the carbonate system in both sea ice and the water column. Therefore, we propose that carbonate minerals, released along with glacial drainage, dissolve in both sea ice and the water column, affecting the carbonate system. This suggests that increasing inputs of glacial meltwater may compensate for the lack of ikaite precipitation within sea ice by increasing glacier-derived carbonate minerals to the ocean and incorporation within the ice structure. If widespread in glacial-fed waters, bedrock carbonate minerals could increase CO2 sequestration in glacial catchments despite the weakening of the sea ice carbon pump.