DOI: 10.1111/gcb.12112
论文题名: Linking temperature sensitivity of soil organic matter decomposition to its molecular structure, accessibility, and microbial physiology
作者: Wagai R. ; Kishimoto-Mo A.W. ; Yonemura S. ; Shirato Y. ; Hiradate S. ; Yagasaki Y.
刊名: Global Change Biology
ISSN: 13541013
出版年: 2013
卷: 19, 期: 4 起始页码: 1114
结束页码: 1125
语种: 英语
英文关键词: Activation energy
; Carbon molecular structure
; Carbon use efficiency
; Density fractionation
; Dissolved organic matter
; Enzyme kinetics
; Soil organic matter
; Substrate quality
; Temperature dependency
Scopus关键词: activation energy
; biomass
; carbon
; decomposition
; dissolved organic matter
; enzyme activity
; fractionation
; global warming
; physiology
; reaction kinetics
; soil organic matter
; substrate
; temperature effect
; article
; chemical structure
; microbiology
; nuclear magnetic resonance spectroscopy
; soil
; temperature
; Magnetic Resonance Spectroscopy
; Molecular Structure
; Soil
; Soil Microbiology
; Temperature
英文摘要: Temperature sensitivity of soil organic matter (SOM) decomposition may have a significant impact on global warming. Enzyme-kinetic hypothesis suggests that decomposition of low-quality substrate (recalcitrant molecular structure) requires higher activation energy and thus has greater temperature sensitivity than that of high-quality, labile substrate. Supporting evidence, however, relies largely on indirect indices of substrate quality. Furthermore, the enzyme-substrate reactions that drive decomposition may be regulated by microbial physiology and/or constrained by protective effects of soil mineral matrix. We thus tested the kinetic hypothesis by directly assessing the carbon molecular structure of low-density fraction (LF) which represents readily accessible, mineral-free SOM pool. Using five mineral soil samples of contrasting SOM concentrations, we conducted 30-days incubations (15, 25, and 35 °C) to measure microbial respiration and quantified easily soluble C as well as microbial biomass C pools before and after the incubations. Carbon structure of LFs (<1.6 and 1.6-1.8 g cm-3) and bulk soil was measured by solid-state 13C-NMR. Decomposition Q10 was significantly correlated with the abundance of aromatic plus alkyl-C relative to O-alkyl-C groups in LFs but not in bulk soil fraction or with the indirect C quality indices based on microbial respiration or biomass. The warming did not significantly change the concentration of biomass C or the three types of soluble C despite two- to three-fold increase in respiration. Thus, enhanced microbial maintenance respiration (reduced C-use efficiency) especially in the soils rich in recalcitrant LF might lead to the apparent equilibrium between SOM solubilization and microbial C uptake. Our results showed physical fractionation coupled with direct assessment of molecular structure as an effective approach and supported the enzyme-kinetic interpretation of widely observed C quality-temperature relationship for short-term decomposition. Factors controlling long-term decomposition Q10 are more complex due to protective effect of mineral matrix and thus remain as a central question. © 2012 Blackwell Publishing Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/62479
Appears in Collections: 影响、适应和脆弱性
There are no files associated with this item.
作者单位: National Institute for Agro-Environmental Sciences (NIAES), Tsukuba, Ibaraki, 305-8604, Japan
Recommended Citation:
Wagai R.,Kishimoto-Mo A.W.,Yonemura S.,et al. Linking temperature sensitivity of soil organic matter decomposition to its molecular structure, accessibility, and microbial physiology[J]. Global Change Biology,2013-01-01,19(4)