Detailed vertical profiles of hydrographic data and routine chemical parameters (oxygen, nutrients) were taken in the Amerasian basin of the Arctic Ocean and in the Bering Strait and Chukchi Sea. Correlations of these chemical profiles with water mass sources and mixing processes are postulated. The chemical parameters show that the water of the sharp temperature maximum at about 75-meter depth is chemically a mixture of the arctic surface water and core water from about 160 meters. This core water corresponds to the temperature minimum and nutrient maximum and is of Bering Strait-Chukchi Sea origin. Chemical parameters clearly show that the temperature maximum and minimum simply reflect differing thermal regimes existing in the Chukchi. Extremely close vertical sampling has shown intriguing detail in the oxygen, temperature, salinity, and nutrient profiles in the area of the very sharp oxygen minimum occurring at about 205 meters. Temperature-salinity and chemical plots of the close-interval data identify a core of water at approximately 230 meters that is mixing above with Bering core water at 160 meters and below with the Atlantic core water at about 500 meters. Thus the oxygen minimum appears to be at least partly due to advection of shelf water into the basin rather than to in situ oxidation alone.