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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #315565

Title: Microbial Contribution to Organic Carbon Sequestration in Mineral Soil

item GRANT, MICHAEL - Washington State University
item SHI, ZHENQING - Washington State University
item KELLER, KENT - Washington State University
item Thomashow, Linda
item SULLIVAN-GUEST, TARAH - Washington State University
item DOHNALKOVA, ALICE - Pacific Northwest National Laboratory
item HARSH, JIM - Washington State University

Submitted to: Soil Science Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 11/20/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Soil productivity and sustainability are dependent on soil organic matter (SOM). Our understanding on how organic inputs to soil from microbial processes become converted to SOM is still limited. This study aims to understand how microbes affect carbon (C) sequestration and the formation of recalcitrant SOM (RSOM) in soil. We hypothesize that biofilm formation on mineral surfaces is an important first step toward the formation of mineral-organic complexes that eventually form RSOM in soil, a process mediated by minerals, plant roots, nutrients, and other environmental factors. Specifically, we are studying the formation of biofilms on typical mineral surfaces to determine how the lability of biofilm-associated C is affected by properties of mineral surfaces, plant roots and microbes. We conducted laboratory microbe growth experiments in batch reactors and replicated columns with or without plant growth. At selected times, we collected mineral, soil, and biomass samples to conduct a variety of analyses to evaluate the changes of C pools. The labile fraction of the biomaterials on mineral surfaces was determined by sequential oxidation with permanganate salt, and total biomaterials were determined with total organic C analysis. We quantified the microbially-mediated change of RSOM pools by analysis of microbial biomarker amino sugars in soil. We determined the biofilm compositions on mineral surfaces using spectroscopic and microscopic techniques including NMR, FTIR, SEM and TEM. Our results illustrate the role of the mineral surface in biofilm formation and how formation of RSOM depends on the interaction between microbes and minerals. This study advances our fundamental understanding of mechanisms of SOM production and retention in soil.