Differences in Organic Matter from a Range of Soil Types and Ecosystems


Organic matter in soils is a key reservoir for carbon and plays a significant role in nutrient biogeochemical cycling. Because of limited understanding of the molecular composition of soil organic matter (SOM), scientists are challenged to decipher the range of chemical processes in soils and to predict how terrestrial carbon fluxes will respond to changing climatic conditions and land use. To address this need, a team of scientists from the University of Idaho and Department of Energy’s Environmental Molecular Sciences Laboratory (EMSL) extracted SOM from multiple ecosystems using a variety of organic solvents, and then analyzed the SOM using EMSL’s ultra-high resolution mass spectrometry capabilities. The team found different solvents extracted different types of compounds from soils, significantly expanding the ability to sensitively detect and identify the vast suite of diverse organic molecules that compose SOM. These findings enable targeted extraction approaches to elucidate differences in organic matter among soils from different ecosystems. These findings also demonstrate that by using multiple solvents on the same soil material, scientists will be able to obtain a more complete characterization of the organic matter in a specific soil sample. Increased understanding of SOM composition in soils from multiple ecosystems is expected to improve predictions of how terrestrial carbon fluxes will respond to future climate change.

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Tfaily, M., R. K. Chu, N. Tolic, K. M. Roscioli, C. R. Anderton, L. Paša-Tolic, E. W. Robinson, and N. J. Hess. 2015. “Advanced Solvent Based Methods for Molecular Characterization of Soil Organic Matter by High Resolution Mass Spectrometry,” Analytical Chemistry 87(10), 5206-15. DOI: 10.1021/acs.analchem.5b00116.