Research Objectives:
This project will analyze air samples from Palmer and South Pole stations to assess variations in the oxygen content in the atmosphere. At Palmer Station, researchers expect to see variations caused by exchanges of oxygen between the atmosphere and the Southern Ocean. The oceans tend to be a source of oxygen to the air in the spring and summer, and a sink for oxygen in the fall and winter. The spring emissions are mostly due to photosynthesis in the water while the winter uptake is due to mixing processes, which bring oxygen depleted waters from depth up to the surface. These exchanges lead to variations in the oxygen content of the air above the water and these changes are rapidly mixed around the latitude band by zonal winds.
Measurements of the seasonal variations in oxygen content at the South Pole, Palmer Station and other sites may be valuable for documenting changes in the biological productivity of the Southern Ocean over time. This project includes a subset of sample collections being made at a series of baseline sites around the world.
This research should help to improve estimates of the processes whereby oxygen is cycled throughout the global ecosystem, specifically, through photosynthesis and atmospheric mixing rates. It can improve predictions of the net exchange rates of carbon dioxide with biota, on land and in the oceans. An important part of the measurement program entails developing absolute standards for oxygen-in-air, to ensure stable long-term calibration. This group will also conduct surveys of the oxidative oxygen/carbon ratios of both terrestrial- and marine-based organic carbon, hoping to improve the quantitative basis for linking the oxygen and carbon dioxide geochemical cycles.
These results should help enhance understanding of the processes that regulate the buildup of carbon dioxide in the atmosphere and of the change processes -- especially climate change -- that regulate ecological functions on land and in the sea.
