Smis,A., Van Damme,S., Struyf,E., Clymans,W., Van Wesemael,B., Frot,E., Vandevenne,F., Van Hoestenberghe,T., Govers,G. and Meire,P.(2011): A trade-off between dissolved and amorphous silica transport during peak flow events (Sceldt river basin, Belgium): impacts of precipitation intensity on terrestrial Si dynamics in strongly cultivated catchments. Biogeochemistry, 106, 475-487.

『ピーク流イベント(ベルギーのスヘルデ川流域)中の溶存および非晶質シリカ移動間のトレードオフ:強く開墾された集水域における陸上ケイ素ダイナミクスへの降水強度の影響』


Abstract
 Amorphous, biogenic Si (ASi) is stored in large amounts in terrestrial ecosystems. The study of terrestrial ASi mobilization remains in the pioneer research stage: most Si budget studies have not included the biogenic amorphous Si stock and fluxes. This hampers our ability to accurately quantify terrestrial mobilization of Si, which is - through ocean carbon burial and CO2 uptake during terrestrial Si weathering - intricately linked to global carbon budgets. We studied detailed concentration and load patterns of dissolved (DSi) and ASi during several high-discharge events in eight first-order river basins. Based on high frequency discharge measurements and concurrent analysis of ASi and DSi concentrations at base flow and during intense precipitation events, we were able to attribute a percentage of yearly ASi and DSi fluxes to both base flow and precipitation event related surface run-off. Our results show ASi and DSi concentrations in upstream river basins to be intricately linked to each other and to discharge, and ASi transport constitutes an important part to the total transport of Si even through first-order river basins (up to 40%). Based on our observations, increased occurrence of peak-discharge events with global climatic changes, and lowered importance of base flow, will coincide with drastic changes in ASi and DSi dynamics in the river continuum. Our work clearly shows ASi dynamics should be incorporated in global Si budgets now, even in low-order small river basins.

Keywords: Amorphous silica; Rain events; Suspended matter; Erosion; Global silica cycle; Land use; Precipitation intensity』

Introduction
Materials and methods
 Study area
 Sample collection
 Base flow separation
 Analysis
 Annual load calculations
Results
 Discharge
 DSi and ASi concentrations
 Suspended matter and TOC concentrations
 Annual load
Discussion
 A trade-off between DSi and ASi
 The dynamics of the continental ASi pool
Conclusions
Acknowledgments
References


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