9528546 Key This is a collaborative study of deep and bottom water formation in the southern sector of the Indian Ocean, as part of the World Ocean Circulation Experiment (WOCE) Indian Ocean Expedition (IOE). Six PIs from six institutions will complete the final segment of the WOCE Hydrographic Program Line, S-4, along 60 degrees South from about 20 degrees East to about 120 degrees East. The program is designed to detect subtle differences across the Kerguelen Plateau, an important hydrographic boundary for bottom waters. In addition to hydrography, the section will include standard tracer measurements, as well as CFCs, Helium, Tritium, and Carbon-14, all to WOCE standards. In addition to the zonal line, two excursions to the shelf at about 54 degrees East and 96 degrees East will be made to investigate the Antarctic Slope Front and its associated westward current. Expendable current moorings will also be deployed at several locations to measure, for one year, the current along the slope and on the flanks of the Kerguelen Plateau.