Variable fluxes of dissolved organic carbon species (DOC) due to the interaction between groundwater discharge and development of permafrost can potentially disturb the carbon cycle as well as biogeochemistry in the bottom water. For this reason, we also measure DOC concentration. The DOC analysis are performed in TOC-L analyzer (Shimadzu). In order to remove inorganic carbon a filtered and acidified water sample, before measurement, is sparged with synthetic air. The method is based on oxidation method with Pt catalyst in high temperature (680°C). Non-purgeable organic carbon compounds are combusted and converted to CO2, which is detected by a nondispersive infrared detector (NDIR). Person responsible for these analysis is Aleksandra Winogradow, Ph.D. .