Probing Temperature-Dependent Organo-mineral Interactions with Molecular Spectroscopy and Quartz Crystal Microgravimetry

Abstract

The global-scale cycling of carbon and mechanisms of carbon storage are important in climate change issues. It is uncertain as to whether climate change will turn soil into a carbon source or change its ability to serve as a sink. In fact, 50–75 % of all natural organic matter (NOM) in soils and sediments is associated with mineral surfaces. These organo-mineral associations can protect NOM from decomposition for timescales of centuries to millennia and serve as a mechanism by which carbon is stored in soils. The stability of organo-mineral complexes, defined as the degree of resistance to decomposition, could affect carbon storage as temperatures increase. The temperature-dependence of the kinetics and mechanisms of carbon stabilization need to be studied for the purpose of developing models to predict how soil carbon reservoirs respond to changes in temperature. Several techniques are proposed to be used in organo-mineral interaction studies. Nuclear magnetic resonance spectroscopy, x-ray photoelectron spectroscopy, and quartz crystal microgravimetry are discussed as potential tools to identify chemical bonding environment and adsorption/desorption dynamics.