DOI: 10.1038/ngeo2940
论文题名: Thermodynamically controlled preservation of organic carbon in floodplains
作者: Boye K. ; Noël V. ; Tfaily M.M. ; Bone S.E. ; Williams K.H. ; Bargar J.R. ; Fendorf S.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2017
卷: 10, 期: 6 起始页码: 415
结束页码: 419
语种: 英语
Scopus关键词: anoxic conditions
; carbon cycle
; decomposition
; floodplain
; microbial activity
; organic carbon
; oxidation
; solubility
; sulfate
; thermodynamics
英文摘要: Organic matter decomposition in soils and terrestrial sediments has a prominent role in the global carbon cycle. Carbon stocks in anoxic environments, such as wetlands and the subsurface of floodplains, are large and presumed to decompose slowly. The degree of microbial respiration in anoxic environments is typically thought to depend on the energetics of available terminal electron acceptors such as nitrate or sulfate; microbes couple the reduction of these compounds to the oxidation of organic carbon. However, it is also possible that the energetics of the organic carbon itself can determine whether it is decomposed. Here we examined water-soluble organic carbon by Fourier-transform ion-cyclotron-resonance mass spectrometry to compare the chemical composition and average nominal oxidation state of carbon-A metric reflecting whether microbial oxidation of organic matter is thermodynamically favourable-in anoxic (sulfidic) and oxic (non-sulfidic) floodplain sediments. We observed distinct minima in the average nominal oxidation state of water-soluble carbon in sediments exhibiting anoxic, sulfate-reducing conditions, suggesting preservation of carbon compounds with nominal oxidation states below the threshold that makes microbial sulfate reduction thermodynamically favourable. We conclude that thermodynamic limitations constitute an important complement to other mechanisms of carbon preservation, such as enzymatic restrictions and mineral association, within anaerobic environments. © 2017 Macmillan Publishers Limited, part of Springer Nature. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/105779
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, United States; Earth System Science Department, Stanford University, Stanford, CA, United States; Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richmond, WA, United States; Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
Recommended Citation:
Boye K.,Noël V.,Tfaily M.M.,et al. Thermodynamically controlled preservation of organic carbon in floodplains[J]. Nature Geoscience,2017-01-01,10(6)