Towards a paradigm shift in the modeling of soil organic carbon decomposition for earth system models

<p>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. </p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Earth, Atmospheric, and Planetary Sciences

Year

2014

Author dc:creator

• He, Yujie

Contributors dc:contributor

• Qianlai Zhuang
• Laura Bowling
• Jennifer Harden
• Greg Michalski
• Jeffrey Dukes

• Atmospheric Sciences
• Biochemistry
• Biology
• Chemistry
• Ecology and Evolutionary Biology

Repository record dc:identifier

https://docs.lib.purdue.edu/open_access_dissertations/282

OAI identifier oai:identifier

oai:docs.lib.purdue.edu:open_access_dissertations-1341