Monson 9814507 Studies will be conducted to develop a new technique for capturing air drafts above a forest canopy. The air drafts will be captured in such a way that we can accurately analyze the stable isotopes of carbon and oxygen in carbon dioxide molecules. The relative fractions of the different isotopes will allow us to separate and study the magnitude of soil respiration and photosynthesis within the forest ecosystem. These studies, in turn, will allow us to determine how much carbon dioxide from the atmosphere is being accumulated in the forest (i.e., the photosynthesis minus respiration), and whether future changes in climate will affect this accumulation by stimulating respiration more than photosynthesis. In this proposal, the PIs will only test and develop the technique. The funds will be used to support three campaigns at different times of the year in an oak-hickory forest in western Tennessee. Future efforts will be aimed at applying the technique to different types of ecosystems. With this technique, the PIs will be able to better assess the role of forests in the global carbon balance.
