Linking soil respiration to hydrologic conditions and climate change
Respiration of organic carbon in soils is one of the largest terrestrial sources of atmospheric CO2 and shifts in the rate of this flux poses one of the largest potential impacts on global warming. Previous studies have found that temperature and soil moisture contents exert first order controls on soil carbon respiration rate using both laboratory incubation experiments and field measurements, however, extrapolations from the respiration rates measured for specific soil samples to environmental systems are still challenged. Multiple mechanisms have been proposed to create the relationship between these environmental factors and soil respiration rate. Yet the application of such mechanisms into high-performance reactive transport frameworks is sparse and incomplete, and thus currently limits cross-field interpolations. To fill in these gaps, I have established a novel process-based reactive transport framework incorporating the transition between active and dormant biomass as a function of soil moisture, to improve the accuracy of model simulations in reproducing data collected from both incubation experiment and the field. This advanced model is applied to both paleo-studies as a means of more accurately reconstructing past atmospheric CO2 concentration variations, and interpolations to evaluate future climate changes. By comparing the common behavior observed in incubation experiments using sparsely sampled soils and a compiled dataset including 436 incubation datasets collected across the globe, this work further guides the spatial upscaling of current numerical simulations.
Soil respiration, Reactive transport model, Soil incubation
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign