DOI: 10.5194/hess-19-3333-2015
Scopus记录号: 2-s2.0-84938635102
论文题名: Landscape heterogeneity drives contrasting concentration-discharge relationships in shale headwater catchments
作者: Herndon E ; M ; , Dere A ; L ; , Sullivan P ; L ; , Norris D ; , Reynolds B ; , Brantley S ; L
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2015
卷: 19, 期: 8 起始页码: 3333
结束页码: 3347
语种: 英语
Scopus关键词: Biogeochemistry
; Biological materials
; Carbon
; Forestry
; Manganese
; Organic carbon
; Organic compounds
; Rain
; Runoff
; Shale
; Soil moisture
; Soils
; Solute transport
; Vegetation
; Water
; Biogeochemical process
; Dissolved organic carbon
; Hydrologic connectivity
; Landscape heterogeneities
; Soil organic matters
; Soil solution chemistry
; Solute concentrations
; Spatially homogeneous
; Catchments
; biogeochemical cycle
; catchment
; concentration (composition)
; discharge
; dissolved organic carbon
; headwater
; landscape structure
; mineral
; rainfall
; soil chemistry
; soil organic matter
; solute transport
; vegetation structure
; Biochemistry
; Concentration
; Hydrology
; Pennsylvania
; Rivers
; Pennsylvania
; United Kingdom
; United States
; Wales
英文摘要: Solute concentrations in stream water vary with discharge in patterns that record complex feedbacks between hydrologic and biogeochemical processes. In a comparison of three shale-underlain headwater catchments located in Pennsylvania, USA (the forested Shale Hills Critical Zone Observatory), and Wales, UK (the peatland-dominated Upper Hafren and forest-dominated Upper Hore catchments in the Plynlimon forest), dissimilar concentration-discharge (C-Q) behaviors are best explained by contrasting landscape distributions of soil solution chemistry - especially dissolved organic carbon (DOC) - that have been established by patterns of vegetation and soil organic matter (SOM). Specifically, elements that are concentrated in organic-rich soils due to biotic cycling (Mn, Ca, K) or that form strong complexes with DOC (Fe, Al) are spatially heterogeneous in pore waters because organic matter is heterogeneously distributed across the catchments. These solutes exhibit non-chemostatic behavior in the streams, and solute concentrations either decrease (Shale Hills) or increase (Plynlimon) with increasing discharge. In contrast, solutes that are concentrated in soil minerals and form only weak complexes with DOC (Na, Mg, Si) are spatially homogeneous in pore waters across each catchment. These solutes are chemostatic in that their stream concentrations vary little with stream discharge, likely because these solutes are released quickly from exchange sites in the soils during rainfall events. Furthermore, concentration-discharge relationships of non-chemostatic solutes changed following tree harvest in the Upper Hore catchment in Plynlimon, while no changes were observed for chemostatic solutes, underscoring the role of vegetation in regulating the concentrations of certain elements in the stream. These results indicate that differences in the hydrologic connectivity of organic-rich soils to the stream drive differences in concentration behavior between catchments. As such, in catchments where SOM is dominantly in lowlands (e.g., Shale Hills), we infer that non-chemostatic elements associated with organic matter are released to the stream early during rainfall events, whereas in catchments where SOM is dominantly in uplands (e.g., Plynlimon), these non-chemostatic elements are released later during rainfall events. The distribution of SOM across the landscape is thus a key component for predictive models of solute transport in headwater catchments. © Author(s) 2015. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78458
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Geosciences, Pennsylvania State University, University Park, PA, United States; Centre for Ecology and Hydrology, Bangor, Gwynedd, United Kingdom; Department of Geology, Kent State University, Kent, OH, United States; Department of Geography/Geology, University of Nebraska at Omaha, Omaha, NE, United States; Department of Geography, University of Kansas, Lawrence, KS, United States
Recommended Citation:
Herndon E,M,, Dere A,et al. Landscape heterogeneity drives contrasting concentration-discharge relationships in shale headwater catchments[J]. Hydrology and Earth System Sciences,2015-01-01,19(8)