| 项目编号: | 1349269
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| 项目名称: | A Cross Site Study of Silica Dynamics in the Critical Zone |
| 作者: | Louis Derry
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| 承担单位: | Cornell University
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| 批准年: | 2013
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| 开始日期: | 2014-04-01
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| 结束日期: | 2018-03-31
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| 资助金额: | USD337761
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| 资助来源: | US-NSF
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| 项目类别: | Standard Grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Earth Sciences
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| 英文关键词: | silica
; si
; czo site
; stream discharge
; nsf critical zone observatory network
; use
; solute concentration
; critical zone
; project
; solute load
; critical zone observatories
; critical zone science community
; silica generation
; water quality
|
| 英文摘要: | This project proposes to investigate the dynamics of silica generation and transport across a series of stream catchments within the NSF Critical Zone Observatory Network (CZO). Solute concentrations and chemical compositions vary with stream discharge in complex ways. In some cases, solute load varies only slightly with stream discharge. In others, solute concentrations drop as discharge increases, showing effects of dilution, but even in these systems dilution is only partial. If stream discharge increases while solute concentration remains near constant, then the total solute load most also increase. An important question in hydrogeochemistry is where does this increase in solute flux come from? Do streams simply sample "more of the same", or are new sources and pathways activated at high flow? In other words, how does water quality vary with discharge, and why? Silica (Si) is well suited for addressing this question as it is primarily sourced from rock and soil weathering reactions, and has a long history of use as a hydrologic tracer. Investigator has previously shown that germanium/silicon ratios can be used to identify specific sources of Si in a catchment, and substantially improve the utility of Si as a tracer. Preliminary data indicate that increased in Si flux associated with high discharge activate new sources of Si. This study will use a series of catchments at CZO sites that have similar rock type but different climate, vegetation, and hydrochemical response patterns in order to learn more about the fundamental controls on solute sources and water quality.
The proposed research will provide new constraints on the geochemical and hydrological processes that control Si fluxes from granitoid weathering in the critical zone. It will address the causes of different concentration-discharge patterns in streams, providing insight into the coupling of weathering and hydrologic processes, and providing an improved basis for hydrograph separation/flow path modeling.
The project will use novel geochemical tracers and the network of Critical Zone Observatories to understand some of the major controls on soil and ground water flow paths and water quality in stream catchments. Silica is not only a useful tracer of hydrologic pathways and solute sources, but also an important buffer of stream chemistry, an important nutrient for both aquatic and terrestrial algae and plants, and is tied to the long term weathering sink of carbon dioxide. An improved understanding of both the short term controls on water flow paths and solute loads, and the longer term controls on weathering fluxes is of broad interest. The project includes working with students and researchers from several CZOs, and will train students from other CZO teams in the measurement and use of Ge/Si as a hydrogeochemical tracer. It is expected that this will help increase the understanding and use of Ge/Si and other hydrogeochemical tracers among the Critical Zone science community. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/97118
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| Appears in Collections: | 影响、适应和脆弱性
气候减缓与适应
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| Recommended Citation: | |
Louis Derry. A Cross Site Study of Silica Dynamics in the Critical Zone. 2013-01-01.
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