Oxygen utilization rates in the Nansen Basin, Arctic Ocean: implications for new production

In situ consumption of oxygen is balanced by ventilation if the observed distribution of dissolved oxygen below the euphotic zone is in steady state. Apparent oxygen utilization rates (AOURs) can be estimated from the observed oxygen distribution if the waters of the upper layers can be dated. It has been shown previously that tritium/ 3 He ages can be used, together with observed oxygen concentrations, to estimate AOURs for waters with ages of several months to several decades. This method is applied to data obtained from the Nansen Basin, Arctic Ocean, during the 1987 cruise of F.S. Polarstern. New production is estimated by depth integration of AOURs calculated for several isopycnals to be 19±5 g C m −2 year −1 for the southern part and 3±2 g C m −2 year −1 for the northern part of the Nansen Basin section. The results are discussed and compared with previous estimates based on different methods.