ABSTRACT OPP-9530795 SCHLOSSER, PETER LDEO-COLUMBIA UNIV. The investigator proposes to conduct a research project on a cruise aboard the German research vessel Polarstern as a part of the international initiative ACSYS planned by the World Meteorological Organization. He will make tritium, helium, and oxygen isotope measurements in the eastern Arctic Ocean to determine the extent of Atlantic water that has recently been found to extend much farther into the basin than previously known. The expansion of Atlantic water into the Arctic could be the result of global change in response to a warming climate or a temporary change in circulation due to factors not associated with climate. The data collected on this cruise will fill in an important gap in the Arctic Ocean so that future studies may observe the persistence of the change in circulation within a global change context.