Over het archief
Het OWA, het open archief van het Waterbouwkundig Laboratorium heeft tot doel alle vrij toegankelijke onderzoeksresultaten van dit instituut in digitale vorm aan te bieden. Op die manier wil het de zichtbaarheid, verspreiding en gebruik van deze onderzoeksresultaten, alsook de wetenschappelijke communicatie maximaal bevorderen.
Dit archief wordt uitgebouwd en beheerd volgens de principes van de Open Access Movement, en het daaruit ontstane Open Archives Initiative.
Basisinformatie over ‘Open Access to scholarly information'.
| one publication added to basket [404422] |
Constraining sulfur incorporation in calcite using inorganic precipitation experiments
Karancz, S.; Uchikawa, J.; de Nooijer, L.J.; Wolthers, M.; Conner, K.A.; Hite, C.G.; Zeebe, R.E.; Sharma, S.K.; Reichart, G.-J. (2024). Constraining sulfur incorporation in calcite using inorganic precipitation experiments. Geochim. Cosmochim. Acta 381: 116-130. https://dx.doi.org/10.1016/j.gca.2024.07.034
In: Geochimica et Cosmochimica Acta. Elsevier: Oxford,New York etc.. ISSN 0016-7037; e-ISSN 1872-9533, meer
|   |
| Author keywords |
Calcite growth experiment; Sulfate incorporation; Ion-pair formation; Inorganic carbon chemistry; Proxy |
| Auteurs | | Top |
- Karancz, S., meer
- Uchikawa, J.
- de Nooijer, L.J., meer
|
- Wolthers, M.
- Conner, K.A.
- Hite, C.G.
|
- Zeebe, R.E.
- Sharma, S.K.
- Reichart, G.-J., meer
|
| Abstract |
The sulfur over calcium ratio (S/Ca) in foraminiferal shells was recently proposed as a new and independent proxy for reconstructing marine inorganic carbon chemistry. This new approach assumes that sulfur is incorporated into CaCO3 predominantly in the form of sulfate (SO42−) through lattice substitution for carbonate ions (CO32–), and that S/Ca thus reflects seawater [CO32–]. Although foraminiferal growth experiments validated this approach, field studies showed controversial results suggesting that the potential impact of [CO32–] may be overwritten by one or more parameters. Hence, to better understand the inorganic processes involved, we here investigate S/Ca values in inorganically precipitated CaCO3 (S/Ca(cc)) grown in solutions of CaCl2 − Na2CO3 − Na2SO4 − B(OH)3 − MgCl2. Experimental results indicate the dependence of sulfate partitioning in CaCO3 on the carbon chemistry via changing pH and suggest that faster precipitation rates increase the partition coefficient for sulfur. The S/Ca ratios of our inorganic calcite samples show positive correlation with modelled [CaSO40](aq), but not with the concentration of free SO42− ions. This challenges the traditional model for sulfate incorporation in calcite and implies that the uptake of sulfate potentially occurs via ion-ion pairs rather than being incorporated as single anions. Based on the [Ca2+] dependence via speciation, we here suggest a critical evaluation of this potential proxy. As sulfate complexation seems to control sulfate uptake in inorganic calcite, application as a proxy using foraminiferal calcite may be limited to periods for which seawater chemistry is well-constrained. As foraminiferal calcite growth is modulated by inward Ca2+ flow to the site of calcification coupled to outward H+ pumping, sulfate incorporation as CaSO40 ion-pair in the foraminifer’s shell also provides a mechanistic link for the observed relationship between S/Ca(cc) and [CO32–]. |
IMIS is ontwikkeld en wordt gehost door het VLIZ.
