Molecular Biogeochemistry of Soil Organic Matter with Environmental Change

点击翻译按钮获取中文摘要

The proposed research program will employ an array of novel molecular tools that provide detailed information about soil organic matter (SOM) composition, biogeochemistry and ecosystem function. These tools, which have been pioneered by my research group, involve both targeted and non-targeted approaches using using mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy; arguably two of the most advanced structural techniques available in modern science. These techniques will be used to study the SOM in soil samples collected from several long-term field experiments in collaboration with University researchers in the United States. This program will also examine SOM mechanisms using innovative lab-based experiments. SOM constitutes more than two-thirds of terrestrial carbon stocks yet current and predicted trends with respect to environmental change have resulted in uncertainties about the fate of soil carbon reserves. SOM biogeochemical cycling plays an integral role within the global carbon cycle through the regulation of atmospheric carbon dioxide via the intricate balance between supporting soil microbial respiration and plant photosynthesis. Previous research has hypothesized that SOM composition is highly sensitive to changes in moisture, temperature, atmospheric CO2 levels, and nitrogen deposition, as well as differences related to localized environmental conditions. For example, increases in atmospheric CO2 levels, increased nitrogen deposition, increased soil temperatures and increases in detrital deposition have all been hypothesized to alter soil biogeochemical processes. However, there is a gap in our understanding with respect to the mechanisms of SOM dynamics with long-term environmental change. As such, there is a desperate need to develop and use research tools that can detect shifts in SOM biogeochemistry at the molecular-level that improve the understanding of ecosystem-level responses to environmental change. The proposed research program will study the molecular biogeochemistry of SOM from long-term field sites that focus on soil warming, nitrogen deposition, and shifts in plant detrital inputs in forests. This information will be coupled with that from collaborating Universities and will enable a molecule to ecosystem, bottom-up understanding of SOM biogeochemistry and ecosystem-level responses to environmental change. The proposed research program will also examine SOM protection mechanisms using laboratory studies that employ innovative MS and NMR techniques. Trainees will develop highly desired skills via hands-on training with novel tools used to monitor SOM in the environment. Overall, this research program will identify environmental change impacts on soil carbon cycling and will shape new policies and environmental management practices to ensure the long-term sustainability of soil resources.