A Novel Experimental and Modelling Study of C and N Dynamics Between Litter, Soil and the Atmosphere as Affected by Soil Fauna and Litter Quality

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The decay of dead plant material (litter) is a key process in terrestrial ecosystems. For example, as nutrients essential for soil fertility are released into the soil through decomposition, carbon (C) is released back to the atmosphere in the form of carbon dioxide (CO2), or stored belowground in stable forms. Annually, the CO2 released to the atmosphere by decomposition processes is an order of magnitude higher than the CO2 released by anthropogenic activities. Climate, litter quality and soil animals are key factors controlling litter decay. Current limited knowledge of litter decomposition processes is hampering model predictions of future changes in atmospheric greenhouse gases. The proposed research will result in novel understanding about the influence of soil animals on decomposition. It includes an innovative litter decay experiment in the field, using cutting-edge and traditional methods to unravel questions about carbon and nitrogen (N) transfers from litter to soil and atmosphere. A well designed experimental plan will result in clear demonstrations of the effect of litter quality and soil animals on decomposition processes. The mechanistic understanding of carbon and nitrogen fluxes during litter decomposition will improve ecosystem models and, ultimately, the ability to predict the impact of climate change on soil carbon budgets, nitrogen trace gas fluxes and net greenhouse gas fluxes from ecosystems. The project will be conducted at the Konza prairie, a Long-Term Ecological Research (LTER) site, and thus will contribute to a long-term database on climate change, biodiversity and ecosystem functioning. A graduate class on potential uses of the tracers in ecology will be taught, and additional field and lab opportunities for training for post-doctoral associates, graduate and undergraduate students will be promoted. Further, a discussion group and lecture series on Soil Sustainability and Climate Change to integrate disciplines as part of the School of Global Environmental Sustainability will be initiated. This research will also contribute to the established NSF K-12 activities ongoing at Colorado State University's Natural Resource Ecology Laboratory (NREL).