干旱区生态环境知识资源中心(Arid): Vertical Connectivity Regulates Water Transit Time and Chemical Weathering at the Hillslope Scale

Arid

DOI	10.1029/2020WR029207
	Vertical Connectivity Regulates Water Transit Time and Chemical Weathering at the Hillslope Scale
	Xiao, Dacheng; Brantley, Susan L.; Li, Li
通讯作者	Li, L (corresponding author), Penn State Univ, Dept Civil & Environm Engn, University Pk, PA 16802 USA.
来源期刊	WATER RESOURCES RESEARCH
ISSN	0043-1397
EISSN	1944-7973
出版年	2021
卷号	57 期号:8
英文摘要	How does hillslope structure (e.g., hillslope shape and permeability variation) regulate its hydro-geochemical functioning (flow paths, solute export, chemical weathering)? Numerical reactive transport experiments and particle tracking were used to answer this question. Results underscore the first-order control of permeability variations (with depth) on vertical connectivity (VC), defined as the fraction of water flowing into streams from below the soil zone. Where permeability decreases sharply and VC is low, >95% of water flows through the top 6 m of the subsurface, barely interacting with reactive rock at depth. High VC also elongates mean transit times (MTTs) and weathering rates. VC however is less of an influence under arid climates where long transit times drive weathering to equilibrium. The results lead to three working hypotheses that can be further tested. H1: The permeability variations with depth influence MTTs of stream water more strongly than hillslope shapes; hillslope shapes instead influence the younger fraction of stream water more. H2: High VC arising from high permeability at depths enhances weathering by promoting deeper water penetration and water-rock interactions; the influence of VC weakens under arid climates and larger hillslopes with longer MTTs. H3: VC regulates chemical contrasts between shallow and deep waters (C-ratio) and solute export patterns encapsulated in the power law slope b of concentration-discharge (CQ) relationships. Higher VC leads to similar shallow versus deep water chemistry (C-ratio similar to 1) and more chemostatic CQ patterns. Although supporting data already exist, these hypotheses can be further tested with carefully designed, co-located modeling and measurements of soil, rock, and waters. Broadly, the importance of hillslope subsurface structure (e.g., permeability variation) indicate it is essential in regulating earth surface hydrogeochemical response to changing climate and human activities.
英文关键词	hillslope reactive transport modeling critical zone weathering shallow and deep hypothesis concentration discharge relationship transit time distribution
类型	Article
语种	英语
开放获取类型	hybrid
收录类别	SCI-E
WOS记录号	WOS:000688205400014
WOS关键词	CONCENTRATION-DISCHARGE RELATIONSHIPS ; REACTIVE-TRANSPORT MODEL ; CRITICAL ZONE ; MAGNESITE DISSOLUTION ; ENVIRONMENTAL SYSTEMS ; GEOCHEMICAL EVOLUTION ; FLOW-THROUGH ; CATCHMENT ; CARBON ; RATES
WOS类目	Environmental Sciences ; Limnology ; Water Resources
WOS研究方向	Environmental Sciences & Ecology ; Marine & Freshwater Biology ; Water Resources
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/368566
作者单位	[Xiao, Dacheng] Penn State Univ, Dept Energy & Mineral Engn, University Pk, PA 16802 USA; [Xiao, Dacheng; Li, Li] Penn State Univ, Dept Civil & Environm Engn, University Pk, PA 16802 USA; [Brantley, Susan L.] Penn State Univ, Earth & Environm Syst Inst, University Pk, PA 16802 USA; [Brantley, Susan L.] Penn State Univ, Dept Geosci, University Pk, PA 16802 USA
推荐引用方式 GB/T 7714	Xiao, Dacheng,Brantley, Susan L.,Li, Li. Vertical Connectivity Regulates Water Transit Time and Chemical Weathering at the Hillslope Scale[J],2021,57(8).
APA	Xiao, Dacheng,Brantley, Susan L.,&Li, Li.(2021).Vertical Connectivity Regulates Water Transit Time and Chemical Weathering at the Hillslope Scale.WATER RESOURCES RESEARCH,57(8).
MLA	Xiao, Dacheng,et al."Vertical Connectivity Regulates Water Transit Time and Chemical Weathering at the Hillslope Scale".WATER RESOURCES RESEARCH 57.8(2021).