DOI: 10.5194/hess-21-6185-2017
Scopus记录号: 2-s2.0-85038365763
论文题名: A pore-size classification for peat bogs derived from unsaturated hydraulic properties
作者: Weber T ; K ; D ; , Iden S ; C ; , Durner W
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2017
卷: 21, 期: 12 起始页码: 6185
结束页码: 6200
语种: 英语
Scopus关键词: Atmospheric chemistry
; Carbon
; Moisture
; Peat
; Rain
; Soils
; Wetlands
; Environmental conditions
; Inverse simulation
; Ombrotrophic peatlands
; Size classification
; Soil hydraulic properties
; Unsaturated hydraulic properties
; Van Genuchten-Mualem models
; Variably saturated flow
; Pore size
; diffusion
; environmental conditions
; hydraulic conductivity
; numerical model
; ombrotrophic environment
; peatland
; pedogenesis
; pore space
; redox potential
; soil organic matter
; soil water
; unsaturated medium
; vadose zone
; Bryophyta
; Sphagnum
英文摘要: In ombrotrophic peatlands, the moisture content of the acrotelm (vadoze zone) controls oxygen diffusion rates, redox state, and the turnover of organic matter. Thus, variably saturated flow processes determine whether peatlands act as sinks or sources of atmospheric carbon, and modelling these processes is crucial to assess effects of changed environmental conditions on the future development of these ecosystems. We show that the Richards equation can be used to accurately describe the moisture dynamics under evaporative conditions in variably saturated peat soil, encompassing the transition from the topmost living moss layer to the decomposed peat as part of the vadose zone. Soil hydraulic properties (SHP) were identified by inverse simulation of evaporation experiments on samples from the entire acrotelm. To obtain consistent descriptions of the observations, the traditional van Genuchten-Mualem model was extended to account for non-capillary water storage and flow. We found that the SHP of the uppermost moss layer reflect a pore-size distribution (PSD) that combines three distinct pore systems of the Sphagnum moss. For deeper samples, acrotelm pedogenesis changes the shape of the SHP due to the collapse of inter-plant pores and an infill with smaller particles. This leads to gradually more homogeneous and bi-modal PSDs with increasing depth, which in turn can serve as a proxy for increasing state of pedogenesis in peatlands. From this, we derive a nomenclature and size classification for the pore spaces of Sphagnum mosses and define inter-, intra-, and inner-plant pore spaces, with effective pore diameters of > 300, 300-30, and 30-10 μm, respectively. © 2017 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78973
Appears in Collections: 气候变化事实与影响
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作者单位: Soil Science and Soil Physics Division, Institute of Geoecology, Technische Universität Braunschweig, Langer Kamp 19c, Braunschweig, Germany; Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
Recommended Citation:
Weber T,K,D,et al. A pore-size classification for peat bogs derived from unsaturated hydraulic properties[J]. Hydrology and Earth System Sciences,2017-01-01,21(12)