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Colocalization of Minerals and Persistent Microbial-derived Organic Matter in Soil


EMSL Project ID
60519

Abstract

Microorganisms are considered a dominant source of persistent soil organic matter (SOM); yet the persistence of microbial-derived organic matter (OM) remains to be discovered. In the proposed work we aim to address this knowledge gap by revealing that soil geochemistry (mineralogy, aggregation) influences how long microbial residues persist in soil. For example, OM storage tends to be abundant in soils with high reactive surface areas and short-range order amorphous iron-bearing mineral phases. By identifying the interactions between microbial-derived SOM and soil geochemistry, we aim to assess the relative importance of mineral (abiotic) filters on SOM accumulation and persistence. We are using an isotope tracer incubation study to identify organic carbon pools of microbial origin that persist in soil and contribute to carbon (C) and nutrient retention in soil. We will test our hypothesis: persistent microbial residues accrue in “hot spots” on minerals, where short-range order amorphous iron-bearing mineral is present at the organo-mineral interface. Through collaborations with EMSL, our experimental approach has the potential to demonstrate whether microbial-derived SOM production and persistence are regulated by factors that can be used to predict and manage SOM accumulation in biofuel ecosystems.

Project Details

Start Date
2022-06-01
End Date
2022-09-30
Status
Closed

Team

Principal Investigator

Kirsten Hofmockel
Institution
Pacific Northwest National Laboratory