International: Using 13C NMR spectroscopy to study the influence of litter chemistry on soil organic matter formation in forests

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AbstractOISE-0754731David Eissenstat, Penn StateForests are substantial reservoirs of soil organic matter and are globally significant in the absorption of Carbon; yet changes taking place in forests today and in the future threaten to perturb the Carbon balance of these ecosystems. For example, the identity of dominant tree species in temperate forests is being altered by human-driven changes in climate, fire regimes, and pest or pathogen outbreaks. Very little is known about how these alterations in tree species composition will impact the dynamics of soil organic matter. This proposal addresses fundamental questions and hypotheses regarding soil organic matter formation and recalcitrance. In combination with on-going, complementary analyses of soil organic matter properties at the Polish common garden, this proposal?s Carbon-13 nuclear magnetic resonance studies are well positioned to provide new insights regarding the impacts of chemical diversity of plant litter on soil organic matter sources and dynamics.Broader impacts: One application of the results of the work would be to use variation in litter chemistry among tree species to predict the impacts of shifts in tree species composition on soil organic matter dynamics in forests. Accurate estimates of forest Carbon budgets are critical to efforts in the U.S. and abroad to manage Carbon, including trading of Carbon credits and sales of Carbon offsets. By conducting this research with Dr. Ingrid Kögel-Knabner (Technical University of Munich), the U.S. research group will establish new relationships between U.S. and European institutions and enable the utilization of two highly specialized techniques, including physical soil fractionation and Carbon-13 nuclear magnetic resonance spectroscopy.