In this project, PI's from three institutions will carry out sampling on a transect in the Southern Ocean along 65 degrees South latitude across the Ross Sea. The sampling will be carried out on the USSR vessel, R/V IOFFE. Scientists from the Scripps Institution of Oceanography will be responsible for the hydrography and nutrients, while scientists from Oregon State University will provide overall coordination and contribute to the data analysis. The Lamont contribution (this project) will be to acquire and analyze samples for the tracers, Tritium, Helium, Oxygen-18, and Carbon-14. This section constitutes a joint contribution by the USA and the Soviet Union to the International World Ocean Circulation Experiment (WOCE), specifically Hydrographic line S-4.