Abstract:

The Arctic Ocean is a high latitude ocean that is also an important CO₂ sink. Its climate and environment are undergoing rapid changes, modifying and increasing the uncertainties associated with its CO₂ absorption capacity. The partial pressure of CO₂ in the surface seawater (pCO₂) is an important indicator of CO₂ absorption capacity. Its distribution across the Arctic Ocean varies. The factors controlling pCO₂ distribution are becoming more complex as a result of the rapid changes in the Arctic Ocean. We reviewed current international research on the present Arctic Ocean carbon sink and the associated uncertainties. We summarized the temporal and spatial distributions of pCO₂ over the Arctic Ocean and identified the main factors controlling rapid changes in pCO₂ distribution. As a result of the rapid changes in the Arctic, the processes and mechanisms of the marine biogeochemical carbon cycle in the Arctic Ocean have also become more complicated, affecting the CO₂ absorption capacity of the Arctic Ocean. Current research shows that with the rapid retreat of sea ice, the Arctic Ocean has gradually strengthened into an important CO₂ sink in the last two decades. The latest research estimated that the Arctic Ocean CO₂ uptake can be as high as 180 TgC·a⁻¹ (1 Tg=10¹² g), with the Chukchi Sea shelf accounting for almost one-third of the total uptake. The Arctic Ocean carbon sink is forecasted to grow in the future. However, actual CO₂ uptake will be lower than estimated, owing to the effects of nutrient supply, surface seawater warming and ocean acidification.

Key words: partial pressure of CO₂(pCO₂), CO₂ sink in the Arctic Ocean, controlling factors, carbon cycle mechanism, Arctic Ocean, rapid Arctic changes