Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Biogeosciences, 8, 89-112, 2011
https://doi.org/10.5194/bg-8-89-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Reviews and syntheses
18 Jan 2011
Tracing the origin of dissolved silicon transferred from various soil-plant systems towards rivers: a review
J.-T. Cornelis1, B. Delvaux1, R. B. Georg2, Y. Lucas3, J. Ranger4, and S. Opfergelt1 1Earth and Life Institute – Environmental Sciences, Université catholique de Louvain, Croix du Sud 2/10, 1348 Louvain-la-Neuve, Belgium
2Trent University, Worsfold Water Quality Centre, 1600 West Bank Dr., Peterborough, Ontario, Canada
3Laboratoire Protee, Université du Sud Toulon Var, BP. 20132, 83957, La Garde, France
4Biogeochemistry of forest ecosystem, INRA Centre de Nancy, 54280 Champenoux, France
Abstract. Silicon (Si) released as H4SiO4 by weathering of Si-containing solid phases is partly recycled through vegetation before its land-to-rivers transfer. By accumulating in terrestrial plants to a similar extent as some major macronutrients (0.1–10% Si dry weight), Si becomes largely mobile in the soil-plant system. Litter-fall leads to a substantial reactive biogenic silica pool in soil, which contributes to the release of dissolved Si (DSi) in soil solution. Understanding the biogeochemical cycle of silicon in surface environments and the DSi export from soils into rivers is crucial given that the marine primary bio-productivity depends on the availability of H4SiO4 for phytoplankton that requires Si. Continental fluxes of DSi seem to be deeply influenced by climate (temperature and runoff) as well as soil-vegetation systems. Therefore, continental areas can be characterized by various abilities to transfer DSi from soil-plant systems towards rivers. Here we pay special attention to those processes taking place in soil-plant systems and controlling the Si transfer towards rivers. We aim at identifying relevant geochemical tracers of Si pathways within the soil-plant system to obtain a better understanding of the origin of DSi exported towards rivers. In this review, we compare different soil-plant systems (weathering-unlimited and weathering-limited environments) and the variations of the geochemical tracers (Ge/Si ratios and δ30Si) in DSi outputs. We recommend the use of biogeochemical tracers in combination with Si mass-balances and detailed physico-chemical characterization of soil-plant systems to allow better insight in the sources and fate of Si in these biogeochemical systems.

Citation: Cornelis, J.-T., Delvaux, B., Georg, R. B., Lucas, Y., Ranger, J., and Opfergelt, S.: Tracing the origin of dissolved silicon transferred from various soil-plant systems towards rivers: a review, Biogeosciences, 8, 89-112, https://doi.org/10.5194/bg-8-89-2011, 2011.
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