Date of Award
Fall 2014
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Earth, Atmospheric, and Planetary Sciences
First Advisor
Qianlai Zhuang
Committee Chair
Qianlai Zhuang
Committee Member 1
Laura Bowling
Committee Member 2
Jennifer Harden
Committee Member 3
Greg Michalski
Committee Member 4
Jeffrey Dukes
Abstract
Soils are the largest terrestrial carbon pools and contain approximately 2200 Pg of carbon. Thus, the dynamics of soil carbon plays an important role in the global carbon cycle and climate system. Earth System Models are used to project future interactions between terrestrial ecosystem carbon dynamics and climate. However, these models often predict a wide range of soil carbon responses and their formulations have lagged behind recent soil science advances, omitting key biogeochemical mechanisms. In contrast, recent mechanistically-based biogeochemical models that explicitly account for microbial biomass pools and enzyme kinetics that catalyze soil carbon decomposition produce notably different results and provide a closer match to recent observations. However, a systematic evaluation of the advantages and disadvantages of the microbial models and how they differ from empirical, first-order formulations in soil decomposition models for soil organic carbon is still needed. This dissertation consists of a series of model sensitivity and uncertainty analyses and identifies dominant decomposition processes in determining soil organic carbon dynamics. Poorly constrained processes or parameters that require more experimental data integration are also identified. This dissertation also demonstrates the critical role of microbial life-history traits (e.g. microbial dormancy) in the modeling of microbial activity in soil organic matter decomposition models. Finally, this study surveys and synthesizes a number of recently published microbial models and provides suggestions for future microbial model developments.
Recommended Citation
He, Yujie, "Towards a paradigm shift in the modeling of soil organic carbon decomposition for earth system models" (2014). Open Access Dissertations. 282.
https://docs.lib.purdue.edu/open_access_dissertations/282
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