『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