Southern Ocean (south of 50°S) accounts for nearly 30-40% of the global oceanic anthropogenic CO₂ (C_ant) absorption, thus has the great potential for C_ant export according to the hypothesis of ‘continental shelf pump (CSP)’. However, the mechanism of CSP in carbon export around coastal Southern Ocean remains limited, implication in the main factors of strong atmospheric CO₂ sink. Here we use chemical tracers to decipher the direction of material exchange during the mixing scheme of shelf waters and deep polar waters in Prydz Bay. Then, the export of C_ant from the Pan-Antarctica shelves to deep Southern Ocean is calculated for the first time, 0.08 Pg C yr^-1 (nearly 40% of the net CO₂ uptake of the global continental shelves, 0.2 Pg C yr^-1) with a 98% of CSP efficiency. The subsequent efficient transport would cause the acidification in deep waters with an average rate of -0.0006 pH unit (1974-2018) and imprint the global carbon cycle via the large-scale thermohaline circulation.
 

pan-Antarctic,carbon uptake,carbon transport