Vertical distributions of strontium 90, cesium 137, and tritium near 45° north in the Atlantic

Data are reported from a section of five stations occupied in 1967 across the North Atlantic at 45°N from 15°W to 41°W; at four stations strontium 90 and tritium were measured on simultaneously collected samples, and several samples were analyzed for cesium 137 as well. Strontium 90 and tritium concentrations show essentially parallel variation with depth of sample; their ratio, however, varies systematically between stations. In the Eastern Basin surface water concentrations extended to about 400-meter depths, whereas in the Western Basin we found two-stepped profiles, the surface concentrations extending only to about 100 meters; in both basins the pronounced major concentration decrease centered about 500-meter depths. In the Western Basin the deep water showed appreciable concentrations of each fallout nuclide, presumably reflecting rapid advection from the Arctic Ocean overflow.