Date of Award
Program or Major
Earth and Environmental Sciences
Doctor of Philosophy
A. Stuart Grandy
Gordon B Bonan
Serita D Frey
Ecological processes drive terrestrial biogeochemistry, yet the incorporation of ecology into the Earth system models that we use to understand and project global change remains. My dissertation focuses on expediting the incorporation of ecology into Earth system models, first by laying out a roadmap from initial assessment of ecological insights to eventual ESM incorporation, and then by demonstrating this roadmap using the example of microbially- controlled carbon and nitrogen cycling in soil. The paradigm around SOM formation and loss has shifted in recent decades away from a focus on the chemically recalcitrant leftovers of litter decomposition and towards a paradigm with microbial residues and mineral interactions at its heart. The MIcrobial-MIneral Carbon Stabilization model (MIMICS) was developed as a way of exploring this new paradigm and examining the relationships between environmental drivers, litter chemistry, microbial physiology, and physical and chemical stabilization mechanisms for SOM. In the first chapter of my dissertation, I document a systematic approach to improve ecological process representation in Earth system models, highlighting multiple points along the way where ecological observations and modeling iteratively strengthen one another. In the second chapter, I develop and validate a new version of MIMICS with coupled N cycling using a large litter decomposition dataset. In the final chapter, I examine MIMICS-CN’s representation of the drivers of SOM C:N ratios using a landscape-scale data synthesis and model-data comparison. Together, these chapters describe and demonstrate the process of improving biogeochemical models along the path to ESMs by introducing new process representations of ecological concepts.
Kyker-Snowman, Emily, "Merging Ecology and Earth System Modeling: Biotic and Abiotic Controls Drive Soil Carbon and Nitrogen Cycling in Microbial-Explicit Soil Biogeochemistry Models" (2021). Doctoral Dissertations. 2624.