Recent variation in air–sea CO₂ flux in the Arctic Ocean is focused. In order to understand the relation between sea ice retreat and CO₂ chemistry, we conducted hydrographic observations in the Arctic Ocean in 2013. There were relatively high pCO₂ surface layer and low pCO₂ subsurface layer in the Canada Basin. The former was due to near-equilibration with the atmosphere and the latter primary production. Both were unlikely mixed by disturbance as large sea-ice melt formed strong stratification.