Details
Original language | English |
---|---|
Article number | 107912 |
Journal | Soil Biology and Biochemistry |
Volume | 148 |
Early online date | 6 Jul 2020 |
Publication status | Published - Sept 2020 |
Abstract
During the last decade, a paradigmatic shift regarding which processes determine the persistence of soil organic matter (SOM) took place. The interaction between microbial decomposition and association of organic matter with the soil mineral matrix has been identified as a focal point for understanding the formation of stable SOM. Using an improved version of the vertically resolved SOM model COMISSION (Ahrens et al., 2015), this paper investigates the effect of a maximum sorption capacity (Qmax) for mineral-associated organic matter (MAOM) formation and its interaction with microbial processes, such as microbial decomposition and microbial necromass production. We define and estimate the maximum sorption capacity Qmax with quantile regressions between mineral-associated organic carbon (MAOC) and the clay plus silt (<20 μm) content. In the COMISSION v2.0 model, plant- and microbial-derived dissolved organic matter (DOM) and dead microbial cell walls can sorb to mineral surfaces up to Qmax. MAOC can only be decomposed by microorganisms after desorption. We calibrated the COMISSION v2.0 model with data from ten different sites with widely varying textures and Qmax values. COMISSION v2.0 was able to fit the MAOC and SOC depth profiles, as well as the respective 14C gradients with soil depth across these sites. Using the generic set of parameters retrieved in the multi-site calibration, we conducted model experiments to isolate the effects of varying Qmax, point-of-entry of litter inputs, and soil temperature. Across the ten sites, the combination of depolymerization limitation of microorganisms due to substrate scarcity in the subsoil and the size of Qmax explain 14C depth gradients in OC.
Keywords
- C, Microbial model, Mineral-associated organic carbon, Organo-mineral interactions, Sorption capacity, Vertical SOC model
ASJC Scopus subject areas
- Immunology and Microbiology(all)
- Microbiology
- Agricultural and Biological Sciences(all)
- Soil Science
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In: Soil Biology and Biochemistry, Vol. 148, 107912, 09.2020.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Combination of energy limitation and sorption capacity explains 14C depth gradients
AU - Ahrens, Bernhard
AU - Guggenberger, Georg
AU - Rethemeyer, Janet
AU - John, Stephan
AU - Marschner, Bernd
AU - Heinze, Stefanie
AU - Angst, Gerrit
AU - Mueller, Carsten W.
AU - Kögel-Knabner, Ingrid
AU - Leuschner, Christoph
AU - Hertel, Dietrich
AU - Bachmann, Jörg
AU - Reichstein, Markus
AU - Schrumpf, Marion
N1 - Funding Information: This study was financially supported by the Deutsche Forschungsgemeinschaft and is part of the research unit FOR1806 “The Forgotten Part of Carbon Cycling: Organic Matter Storage and Turnover in Subsoils (SUBSOM)”. We thank everyone in the Research Unit for measuring a lot of samples and countless hours of fieldwork. This manuscript benefited greatly from the input and critique of two anonymous reviewers. We thank them and Editor in Chief Dr Josh Schimel for their feedback and time investment.
PY - 2020/9
Y1 - 2020/9
N2 - During the last decade, a paradigmatic shift regarding which processes determine the persistence of soil organic matter (SOM) took place. The interaction between microbial decomposition and association of organic matter with the soil mineral matrix has been identified as a focal point for understanding the formation of stable SOM. Using an improved version of the vertically resolved SOM model COMISSION (Ahrens et al., 2015), this paper investigates the effect of a maximum sorption capacity (Qmax) for mineral-associated organic matter (MAOM) formation and its interaction with microbial processes, such as microbial decomposition and microbial necromass production. We define and estimate the maximum sorption capacity Qmax with quantile regressions between mineral-associated organic carbon (MAOC) and the clay plus silt (<20 μm) content. In the COMISSION v2.0 model, plant- and microbial-derived dissolved organic matter (DOM) and dead microbial cell walls can sorb to mineral surfaces up to Qmax. MAOC can only be decomposed by microorganisms after desorption. We calibrated the COMISSION v2.0 model with data from ten different sites with widely varying textures and Qmax values. COMISSION v2.0 was able to fit the MAOC and SOC depth profiles, as well as the respective 14C gradients with soil depth across these sites. Using the generic set of parameters retrieved in the multi-site calibration, we conducted model experiments to isolate the effects of varying Qmax, point-of-entry of litter inputs, and soil temperature. Across the ten sites, the combination of depolymerization limitation of microorganisms due to substrate scarcity in the subsoil and the size of Qmax explain 14C depth gradients in OC.
AB - During the last decade, a paradigmatic shift regarding which processes determine the persistence of soil organic matter (SOM) took place. The interaction between microbial decomposition and association of organic matter with the soil mineral matrix has been identified as a focal point for understanding the formation of stable SOM. Using an improved version of the vertically resolved SOM model COMISSION (Ahrens et al., 2015), this paper investigates the effect of a maximum sorption capacity (Qmax) for mineral-associated organic matter (MAOM) formation and its interaction with microbial processes, such as microbial decomposition and microbial necromass production. We define and estimate the maximum sorption capacity Qmax with quantile regressions between mineral-associated organic carbon (MAOC) and the clay plus silt (<20 μm) content. In the COMISSION v2.0 model, plant- and microbial-derived dissolved organic matter (DOM) and dead microbial cell walls can sorb to mineral surfaces up to Qmax. MAOC can only be decomposed by microorganisms after desorption. We calibrated the COMISSION v2.0 model with data from ten different sites with widely varying textures and Qmax values. COMISSION v2.0 was able to fit the MAOC and SOC depth profiles, as well as the respective 14C gradients with soil depth across these sites. Using the generic set of parameters retrieved in the multi-site calibration, we conducted model experiments to isolate the effects of varying Qmax, point-of-entry of litter inputs, and soil temperature. Across the ten sites, the combination of depolymerization limitation of microorganisms due to substrate scarcity in the subsoil and the size of Qmax explain 14C depth gradients in OC.
KW - C
KW - Microbial model
KW - Mineral-associated organic carbon
KW - Organo-mineral interactions
KW - Sorption capacity
KW - Vertical SOC model
UR - http://www.scopus.com/inward/record.url?scp=85089277024&partnerID=8YFLogxK
U2 - 10.1016/j.soilbio.2020.107912
DO - 10.1016/j.soilbio.2020.107912
M3 - Article
AN - SCOPUS:85089277024
VL - 148
JO - Soil Biology and Biochemistry
JF - Soil Biology and Biochemistry
SN - 0038-0717
M1 - 107912
ER -