Calcium carbonate cycling in the Southern Ocean: insights from dissolved calcium and potential alkalinity tracers

Abstract The cycling of calcium carbonate (CaCO 3 ) plays a significant role in deep‐water carbon sequestration and affects the buffer capacity of the upper ocean for absorbing atmospheric CO 2 . This study investigates the role of dissolved calcium (Ca) and potential alkalinity (PA) as tracers for CaCO 3 cycling in the Southern Ocean. The correlation between PA and Ca concentrations in subantarctic and polar waters supports their use as effective tracers of the process of CaCO 3 dissolution and precipitation. Estimates of particulate inorganic carbon export flux based on Ca concentration reveals substantial contributions in the Southern Ocean, with higher values in the subantarctic waters. These findings highlight the value of Ca and PA as tracers for understanding CaCO 3 cycling and its role in carbon sequestration and buffering atmospheric CO 2 .