PhD Integrating biological and chemical soil processes to predict the climate-soil carbon feedback

Project: PhD

Project Details

Description

Biotic and abiotic processes responsible for the land carbon-climate feedback are significantly affected by temperature changes. This is known as temperature sensitivity. The temperature sensitivity of abiotic processes can be described by the Arrhenius theory. While, the temperature sensitivity of biotic processes is better explained by the macro-molecular rate theory (MMRT). Yet, a universal equation that accounts for both types of processes is still missing from models predicting the effect of climate warming on soil carbon. This PhD will develop, calibrate, and validate a new equation that combines the Arrhenius and MMRT functions to account for the dual biological and chemical nature of soil organic matter (SOM) decomposition. I propose to conduct a series of laboratory incubations along with modelling work. First, using an European database I will identify a large range of samples with varying ratios of particulate organic matter (POM) to mineral-associated organic matter (MAOM). Second, I will use the Rock-Eval (RE) technique on these samples to translate POM and MAOM proportions into quantifiable thermal and compositional indicators related to their position on an abiotic-biotic gradient. I will characterize the temperature response of these samples in a laboratory incubation experiment. Further, I will use a variety of cost minimization fitting routines to estimate the relative weights of the Arrhenius and MMRT equations as a function of the abiotic-biotic gradient. Finally, I will apply the new equation to characterize how mineralogical composition and microbial communities contribute to explaining variations in the temperature response of SOM decomposition on large spatial and temporal scales.
StatusActive
Effective start/end date1/10/21 → …

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