Portable photosynthesis/respirometer system for the measurement of carbon dioxide fluxes in forest and grassland ecosystems

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There is a general scientific consensus that climate change is occurring and that it is partly induced by human activity as it is caused by an increase in greenhouse gases in the atmosphere. The increase of the most notorious greenhouse gas, carbon dioxide, is mainly due to the burning of fossil fuels and land-use change. Terrestrial ecosystems have the potential to curb these emissions by sequestering large amounts of carbon into their biomass or the soil component. The use of terrestrial ecosystems as a mitigation measure requires, however, further quantitative evidence. My research program examines the influence of climate variability, natural and anthropogenic disturbances, as well as management practices on the carbon sequestration of forest and grassland ecosystems. I use a bottom-up approach, using carbon dioxide flux chamber measurements of photosynthesis and respiration, to partition and scale up component fluxes of carbon dioxide to the ecosystem level. By quantifying the contribution of the soil, grassland and forest vegetation, I determine the sink or source strength of these ecosystems and I assess their responses to different management practices such as nitrogen fertilization and cattle grazing. In this proposal, funds are requested for the acquisition of the core instrument of my research program, i.e. a portable photosynthesis/respirometer system that will be used in various field studies. The results obtained with this instrument will be important to parameterize and validate process-based models of carbon exchange and improve the accuracy of simulations regarding the interactions between climate change and terrestrial ecosystem processes.