Author ORCID Identifier
Semester
Fall
Date of Graduation
2023
Document Type
Thesis
Degree Type
MS
College
Davis College of Agriculture, Natural Resources and Design
Department
Division of Plant and Soil Sciences
Committee Chair
Ember M. Morrissey
Committee Member
Louis M. McDonald
Committee Member
Daniel G. Panaccione
Abstract
The remnants of microorganisms are now understood to account for the majority of organic matter in many mineral soils. Despite the significance of this microbial necromass for soil carbon storage, we know relatively little about how the traits of microorganisms interact with soil minerals to determine the stability of microbe derived carbon in soil. Soil minerals differ in their surface area and chemistry potentially influencing microbial attachment, biofilm formation, and the persistence of microbial necromass. To address this knowledge gap, we grew twelve bacterial species from four broad groups of varying cell wall morphology (Gram positive, Gram negative, filamentous actinobacteria, and capsule-forming bacteria) in 13C-enriched minimal media with soil minerals (sand, clay, goethite-coated sand, and goethite-coated clay). The decomposition of heat-killed and dried necromass-mineral preparations was then traced in a 28-day soil microcosm experiment. Over the incubation period 20–80% of the necromass carbon was respired depending upon both cell wall morphology and mineral chemistry. In general, the necromass carbon from Gram-positive bacteria persisted longer than that of Gram-negative bacteria. Goethite coating on clay tended to reduce decomposition, especially for Gram-positive bacterial necromass (as only ~30% of the C was respired). This may be a consequence of anionic teichoic acids in the cell wall of Gram-positive bacteria adhering to positively charged iron oxides coating the clay mineral surface. Necromass decomposition was greatest for Gram-negative bacteria grown in the presence of sand (50–80% of the necromass C was respired) suggesting that these cells have difficulty forming stable attachments to sand surfaces. Taken together this work suggests that interactions between the surface chemistry of microbial cells and soil minerals may provide new insights into how microbes and minerals interact to influence soil organic matter persistence.
Recommended Citation
Rion, Md Shafiul Islam, "Attachment Issues: Microbes, Minerals, and the Persistence of Soil Organic Matter" (2023). Graduate Theses, Dissertations, and Problem Reports. 12175.
https://researchrepository.wvu.edu/etd/12175