DOI: 10.1002/2014GL061467
论文题名: Invariant soil water potential at zero microbial respiration explained by hydrological discontinuity in dry soils
作者: Manzoni S. ; Katul G.
刊名: Geophysical Research Letters
ISSN: 0094-9704
EISSN: 1944-9435
出版年: 2014
卷: 41, 期: 20 起始页码: 7151
结束页码: 7158
语种: 英语
英文关键词: drought
; microbial water stress
; percolation theory
; soil moisture
; soil respiration
; upscaling
Scopus关键词: Diffusion
; Drought
; Percolation (solid state)
; Soil moisture
; Solvents
; Hydrological connectivity
; Microbial activities
; Microbial respiration
; Percolation theory
; Soil microbial respiration
; Soil respiration
; Upscaling
; Water stress
; Soils
; arid region
; diffusion
; hydraulic conductivity
; hydrological cycle
; microbial activity
; percolation
; soil microorganism
; soil moisture
; soil respiration
; soil water
; upscaling
英文摘要: Soil microbial respiration rates decrease with soil drying, ceasing below water potentials around -15-MPa. A proposed mechanism for this pattern is that under dry conditions, microbes are substrate limited because solute diffusivity is halted due to breaking of water film continuity. However, pore connectivity estimated from hydraulic conductivity and solute diffusivity (at Darcy's scale) is typically interrupted at much less negative water potentials than microbial respiration (-0.1 to -1-MPa). It is hypothesized here that the more negative respiration thresholds than at the Darcy's scale emerge because microbial activity is restricted to microscale soil patches that retain some hydrological connectivity even when it is lost at the macroscale. This hypothesis is explored using results from percolation theory and meta-analyses of respiration-water potential curves and hydrological percolation points. When reducing the spatial scale from macroscale to microscale, hydrological and respiration thresholds become consistent, supporting the proposed hypothesis. Key Points Microbial respiration stops at -15 MPa - less than diffusivity at Darcy scaleDownscaling diffusivity with percolation theory decreases percolation pointsStable percolation points suggest substrate-limited respiration in dry soils ©2014. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84911410724&doi=10.1002%2f2014GL061467&partnerID=40&md5=de8344783fcadaa2c7d7a9d0e4ee2d20
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/6968
Appears in Collections: 气候减缓与适应
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作者单位: Department of Physical Geography and Quaternary Geology, Stockholm University, Stockholm, Sweden
Recommended Citation:
Manzoni S.,Katul G.. Invariant soil water potential at zero microbial respiration explained by hydrological discontinuity in dry soils[J]. Geophysical Research Letters,2014-01-01,41(20).