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Responses of forest soil respiration to elevated CO2

My research focuses on how elevated atmospheric [CO2] affects soil respiration in forest ecosystems and what the consequences for soil C storage will be. Soil respiration is the second largest flux in the global C cycle after plant primary production. Therefore, even a small change in its rate with rising [CO2] could have a substantial impact on atmospheric CO2 accumulation. Soil respiration rates have been shown to almost universally increase under elevated CO2 conditions; however, little is known about how individual soil C pools with different residence times are affected. I work at the Duke Forest FACE site, where an intact loblolly pine forest has been exposed to elevated CO2 since 1996. I use the 13C signature of the fumigation CO2 to study how belowground C pools respond to elevated CO2 conditions. The ecosystem isotope tracer allows the partitioning of the forest's soil respiration flux into the relative contributions from the labile and recalcitrant soil C pools.