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Extreme silicon isotope fractionation due to Si organic complexation: Implications for silica biomineralization

Stamm, Franziska M. LU ; Méheut, Merlin ; Zambardi, Thomas ; Chmeleff, Jérôme ; Schott, Jacques and Oelkers, Eric (2020) In Earth and Planetary Science Letters 541.
Abstract
A combination of theoretical predictions and isotopic equilibration experiments using the three-isotope method have been performed to assess Si isotope fractionation among minerals, and aqueous species in the presence of dissolved catechol. Aqueous Si in abiotic ambient temperature aqueous solutions is dominated by the IV-coordinated H4SiO04species, but the presence of aqueous catechol provokes the formation of a VI-fold Si-catechol complex. Results show an equilibrium Si fractionation factor of ∼19between the VI-fold coordinated Si-catechol complex and the IV-fold coordinated aqueous silicic acid, an amplitude never previously observed for silicon. The fractionation between V-fold Si-organo complexes (with diolate, glyconate or... (More)
A combination of theoretical predictions and isotopic equilibration experiments using the three-isotope method have been performed to assess Si isotope fractionation among minerals, and aqueous species in the presence of dissolved catechol. Aqueous Si in abiotic ambient temperature aqueous solutions is dominated by the IV-coordinated H4SiO04species, but the presence of aqueous catechol provokes the formation of a VI-fold Si-catechol complex. Results show an equilibrium Si fractionation factor of ∼19between the VI-fold coordinated Si-catechol complex and the IV-fold coordinated aqueous silicic acid, an amplitude never previously observed for silicon. The fractionation between V-fold Si-organo complexes (with diolate, glyconate or methyllactate groups) and silicic acid has also been estimated through theoretical predictions to be about −10. These extreme fractionations can be used to improve our ability to interpret the Si isotope compositions of natural solids, and in particular those associated with marine silica biomineralization processes (e.g. sponge spicules). (Less)
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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
silicon, equilibrium isotope fractionation, organo-silicon complexes, first principle calculation, three-isotope method, Si coordination change
in
Earth and Planetary Science Letters
volume
541
article number
116287
pages
12 pages
publisher
Elsevier
external identifiers
  • scopus:85084190709
ISSN
0012-821X
DOI
10.1016/j.epsl.2020.116287
language
English
LU publication?
yes
id
131d3d37-ad29-445f-89c8-a7e58d05f839
date added to LUP
2021-01-22 19:12:26
date last changed
2022-04-26 23:50:51
@article{131d3d37-ad29-445f-89c8-a7e58d05f839,
  abstract     = {{A combination of theoretical predictions and isotopic equilibration experiments using the three-isotope method have been performed to assess Si isotope fractionation among minerals, and aqueous species in the presence of dissolved catechol. Aqueous Si in abiotic ambient temperature aqueous solutions is dominated by the IV-coordinated H4SiO04species, but the presence of aqueous catechol provokes the formation of a VI-fold Si-catechol complex. Results show an equilibrium Si fractionation factor of ∼19between the VI-fold coordinated Si-catechol complex and the IV-fold coordinated aqueous silicic acid, an amplitude never previously observed for silicon. The fractionation between V-fold Si-organo complexes (with diolate, glyconate or methyllactate groups) and silicic acid has also been estimated through theoretical predictions to be about −10. These extreme fractionations can be used to improve our ability to interpret the Si isotope compositions of natural solids, and in particular those associated with marine silica biomineralization processes (e.g. sponge spicules).}},
  author       = {{Stamm, Franziska M. and Méheut, Merlin and Zambardi, Thomas and Chmeleff, Jérôme and Schott, Jacques and Oelkers, Eric}},
  issn         = {{0012-821X}},
  keywords     = {{silicon; equilibrium isotope fractionation; organo-silicon complexes; first principle calculation; three-isotope method; Si coordination change}},
  language     = {{eng}},
  month        = {{05}},
  publisher    = {{Elsevier}},
  series       = {{Earth and Planetary Science Letters}},
  title        = {{Extreme silicon isotope fractionation due to Si organic complexation: Implications for silica biomineralization}},
  url          = {{http://dx.doi.org/10.1016/j.epsl.2020.116287}},
  doi          = {{10.1016/j.epsl.2020.116287}},
  volume       = {{541}},
  year         = {{2020}},
}