This data was used to evaluate links between limnological processes and climate in the article "Regime shifts in lake oxygen and temperature in the rapidly warming high Arctic". The data presented are time series of dissolved oxygen concentrations expressed in percentages and mgL¯¹, temperature in °C, and specific conductivity in µScm¯¹. We installed a mooring below ~1 m-thick ice in the deepest part of 2FB Lake on 26 May 2019 and retrieved it on 1 August 2022. Dissolved oxygen saturation was measured at 0.5, 2, 4 and 6 m, water temperature at 0.5, 1, 1.5, 2, 3, 4, 5 and 6 m, and specific conductivity at 6 m. All depths represent positions below the bottom of the ice at deployment.
