Distribution of radium-224 in the western Arctic Ocean

Radium-224 activities in the western Arctic Ocean were measured via ship-board ²²⁰Rn emanation technique during the Second Chinese National Arctic Expedition. The results showed that the ²²⁴Ra activities in the study areas ranged from being less than 0.08 to 3.58 Bq/m³, with an average of 0.23 Bq/m³. The low ²²⁴Ra concentration in the surface water was attributed to the influence of sea ice melted water. The horizontal distribution of surface ²²⁴Ra in the western Arctic Ocean showed a high ²²⁴Ra characteristics occurred along the slope around 160°W, providing evidence for the importance of ice-rafted sediments to controlling the distribution of radium isotopes in the Arctic Ocean. Mostly, ²²⁴Ra concentrations increased with the depth in the shelf region and reached a maximum at 75 m at the central Canada Basin, which further confirms the importance of the transport of shelf bottom water to maintaining the upper halocline layer in the Canada Basin.