Collection of Tritium/Helium Samples from the Amundsen and Bellinghausen Seas

9412910 Schlosser The proposed work is the collection and analysis of seawater samples for tritium and helium on an oceanographic cruise of the RVIB Nathaniel B. Palmer to the Amundsen and Bellingshausen Seas in early 1994. This region has been sparsely sampled in the past, and little is known about the regional oceanographic processes. The specific objectives of this cruise are to investigate the large-scale oceanographic features, study the evolution of the surface mixed layer and pycnocline in relation to the sea ice cover and the underlying intermediate and deep water masses, determine the location of the Antarctic Slope Front, and to investigate the impact of warm circumpolar water flowing onto the continental shelf. Tritium is particularly useful in determining the rate of penetration of continental shelf waters into deep oceanic basins, while helium, in combination with oxygen isotopes, is a unique tracer for water derived from the basal melting of ice shelves. The proposed work complements these objectives of the cruise, since the physical and chemical characteristics of tritium and helium are well known and well suited for the investigation of subsurface water mass formation and water circulation. Knowledge of the distribution of trace elements in the ocean broadens the time and space scales of the direct observations, and allows inferences about oceanic processes that go beyond the immediate limits of the cruise. ***