9523696 Bender Changes in the concentration of molecular oxygen in air are linked to those of carbon dioxide by photosynthesis, respiration, and combustion. Because of this linkage, distributions of oxygen reflect rates of natural carbon cycling and anthropogenic perturbations in the carbon cycle. An important difference in the behavior of these two gases is that carbon dioxide is much more soluble in the oceans. Because oxygen is so insoluble in seawater, variations in atmospheric oxygen concentrations reflect carbon and oxygen fluxes without the confounding effect of changes in the ocean reservoir. In this project, measurements of the oxygen distribution (actually the oxygen/nitrogen ratio) of air at remote sites will be continued. These measurements will give information about important unresolved fluxes of carbon and oxygen. Specific results anticipated are: 1. Long term records of the oxygen/nitrogen ratio will define the rate at which the oxygen concentration is decreasing with time, which is due to fossil fuel combustion. These data, together with the rate of increase of carbon dioxide, can be interpreted to determine the net rate of change in the land biomass and the rate of carbon dioxide dissolution in the oceans. 2. The seasonal amplitude in oxygen concentration reflects rates of net oceanic production over a large scale. This information is currently not available from any other experimental method. 3. Interannual changes in the magnitude of seasonal variations in the oxygen/nitrogen ratio reflect interannual variations in winds, cloudiness, and ocean circulation. ***
