This Postdoctoral Research Fellowship supports a series of field and laboratory experiments to demonstrate the use of atmospheric carbonyl sulfide (COS) as an independent proxy for terrestrial gross primary production. Gross primary production is the total amount of carbon dioxide "fixed" by land plants per unit time through the photosynthetic reduction of carbon dioxide into organic compounds. It is an important parameter for describing carbon-climate feedbacks, assessing ecosystem-based carbon dioxide capture and storage projects, and as an important input parameter in models of ecosystem carbon exchange. This investigator is actively involved in education and outreach to promote literacy in science.
To use COS exchange as an approximation of carbon uptake on an ecosystem scale, soil exchange rates of COS need to be characterized to distinguish COS plant consumption from COS uptake in soils. The investigator is developing a novel application of the isotope pool dilution technique (using 13COS) to enable measurements of soil COS consumption and production, thereby untangling factors that control net COS exchange. She will conduct controlled laboratory experiments to assess the role of environmental variables such as temperature, UV light, and enzyme activities in soils on the variations in COS exchange. Field measurements will be made at a variety of sites, including at a montane gradient in southern California that is a designated FLUXNET site and at a chaparral and a desert site that is already instrumented with eddy flux towers and continuously monitored environmental variables. FLUXNET is a regional network in which each participating site uses eddy covariance methods to measure the exchanges of carbon dioxide, water vapor, and energy between terrestrial ecosystems and the atmosphere.
This work will take place under the guidance of senior scientists at the University of California Merced and the Lawrence Berkeley National Laboratory.
