Cesium-137 concentrations of surface waters were measured during Cruise 20 of R/V Dmitry Mendeleev across the Atlantic and Pacific Oceans. The measurements were combined with simultaneous salinity measurements. The radioactivity field of surface waters is governed by presence of closed circulation systems and their component currents. Crossing the oceans from west to east decrease in cesium-137 concentrations was noted. In surface waters in the northeastern periphery of the southern anticyclonic gyre in the Pacific Ocean Cs-137 concentrations increased (up to 21.5 Bq/m**3) due to a series of nuclear tests on the Muroroa Atoll.

Supplement to: Domanov, Mikhail M; Poyarkov, Sergey G (1984): Cesium-137 content of the surface water in the Tropical Atlantic and Pacific Oceans (along the route of the 20th cruise of the R/V Dmitriy Mendeleyev). Oceanology, 24(2), 209-214