Biological control of terrestrial silica cycling and export fluxes to watersheds

Silicon has a crucial role in many biogeochemical processesfor example, as a nutrient for marine and terrestrial biota, in buffering soil acidification and in the regulation of atmospheric carbon dioxide. Traditionally, silica fluxes to soil solutions and stream waters are thought to be controlled b...

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Bibliographic Details
Published in:Nature 2005-02, Vol.433 (7027), p.728-731
Main Authors: Derry, L.A, Kurtz, A.C, Ziegler, K, Chadwick, O.A
Format: Article
Language:English
Subjects:
Acidification
basaltic soils
biodegradation
biogeochemical cycles
biological activity in soil
Biological control
Biology
Biomass
Biota
Carbon dioxide
Fresh Water - chemistry
Freshwater
Germanium
Germanium - analysis
Hawaii
Humanities and Social Sciences
letter
Moisture content
multidisciplinary
nutrient uptake
plant litter
Plantae
plants
Plants - metabolism
Science
Science (multidisciplinary)
Silica
Silicon
Silicon - analysis
Silicon Dioxide - analysis
Silicon Dioxide - metabolism
Soil - analysis
Soil acidification
Soil solution
Soil water
Soils
vegetation
Watersheds
Weather
Weathering
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Summary:Silicon has a crucial role in many biogeochemical processesfor example, as a nutrient for marine and terrestrial biota, in buffering soil acidification and in the regulation of atmospheric carbon dioxide. Traditionally, silica fluxes to soil solutions and stream waters are thought to be controlled by the weathering and subsequent dissolution of silicate minerals. Rates of mineral dissolution can be enhanced by biological processes. But plants also take up considerable quantities of silica from soil solution, which is recycled into the soil from falling litter in a separate soil-plant silica cycle that can be significant in comparison with weathering input and hydrologic output. Here we analyse soil water in basaltic soils across the Hawaiian islands to assess the relative contributions of weathering and biogenic silica cycling by using the distinct signatures of the two processes in germanium/silicon ratios. Our data imply that most of the silica released to Hawaiian stream water has passed through the biogenic silica pool, whereas direct mineral-water reactions account for a smaller fraction of the stream silica flux. We expect that other systems exhibiting strong Si depletion of the mineral soils and/or high Si uptake rates by biomass will also have strong biological control on silica cycling and export.
ISSN:0028-0836
1476-4687
DOI:10.1038/nature03299