Department Seminar: Ahra Mo

Title: Understanding What Controls the Inorganic Carbon Parameters in the Arctic Ocean

Abstract: The Arctic Ocean is one of the most rapidly changing regions in the global climate system and serves as a critical sink that regulates the global carbon budget through air–sea CO2 exchange. However, its carbon cycle is not limited to simple uptake and release processes; it is intricately controlled by a combination of factors such as seasonal sea-ice dynamics, atmospheric circulation, ocean currents, and water column structure. Recent studies have drawn particular attention to how sea-ice loss and large-scale circulation changes accelerate both the inorganic carbon cycle and ocean acidification in the Arctic.

In this seminar, I will highlight key processes shaping the inorganic carbon cycle of the Arctic Ocean based on recent field observations. Sea-ice melt not only dilutes surface waters but also enhances biological activity and releases excess alkalinity, together amplifying the uptake of atmospheric CO2. In addition, the subsurface aragonite undersaturation layer is strongly modulated by freshwater dynamics of the Beaufort Gyre and the northward intrusion of Atlantic water masses. These findings suggest that the carbonate chemistry of the Arctic Ocean responds sensitively not only to short-term local factors but also to long-term, basin-scale circulation patterns.

Overall, the results indicate that sea ice functions as an active regulator shaped by coupled chemical and biological processes rather than as a passive barrier. At the same time, large-scale atmosphere–ocean interactions and circulation regimes emerge as key drivers of both the carbon cycle and the vulnerability of the Arctic Ocean to acidification. Ultimately, this research provides important insights into predicting future carbon uptake capacity and the pace of acidification in a rapidly changing Arctic.