Changes in calcium ion concentration as the common driver for Na, K, S, and B incorporation during inorganic calcite precipitation in Mg-free artificial seawater

Joji Uchikawa; Szabina Karancz; Mariëtte Wolthers; Laura Pacho; Dustin T. Harper; Donald E. Penman; Lennart J. de Nooijer; Gert-Jan Reichart; Richard E. Zeebe

doi:10.1016/j.gca.2025.03.022

Changes in calcium ion concentration as the common driver for Na, K, S, and B incorporation during inorganic calcite precipitation in Mg-free artificial seawater

Joji Uchikawa^*
, Szabina Karancz
, Mariëtte Wolthers
, Laura Pacho
, Dustin T. Harper
, Donald E. Penman
, Lennart J. de Nooijer
, Gert-Jan Reichart
, Richard E. Zeebe

^*Corresponding author for this work

Royal Netherlands Institute for Sea Research - NIOZ

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

Calcite is known to incorporate a range of non-constituent ions during its precipitation from aqueous solutions. Their concentrations (measured as E/Ca ratios, where E denotes the elemental forms of non-constituent ions) in calcite formed in seawater can serve as useful tools for paleoceanographic studies. But this requires concrete understanding of the incorporation patterns and their dependence to environmental factors at the time of mineral precipitation. Here, we present Na/Ca, K/Ca, S/Ca, and B/Ca ratios of inorganic calcite samples generated in laboratory experiments using Mg-free artificial seawater with systematic manipulations of pH, [DIC], and [Ca²⁺]. The three parameters were varied both individually (the pH, DIC, and Ca experimental series) and in tandem (the pH-Ca and DIC-Ca series) to form calcites under variable versus near-constant precipitation rates (denoted as R). All measured E/Ca ratios showed a robust positive linear dependence to changes in [Ca²⁺] in the Ca, pH-Ca, and DIC-Ca series, irrespective of changes in R. While K/Ca and S/Ca ratios changed almost exclusively with [Ca²⁺], Na/Ca and B/Ca ratios showed an additionally strong increase with increasing pH and a more moderate increase with rising [DIC], when R changed accordingly in the pH and DIC series. While R-driven kinetic effects and/or formation of certain cation–anion pairs may be important for the elemental uptake in calcite under some circumstances, these mechanisms or processes cannot fully account for the observed trends in every experimental series for all E/Ca ratios considered here. We propose that the observed E/Ca trends can be comprehensively explained by simultaneously considering the nonequivalent influence of changes in solution [Ca²⁺] and [CO₃²⁻] on step-specific kink formation dynamics and the size difference between the respective non-constituent ions (K⁺, Na⁺, SO₄²⁻, and B(OH)₄⁻ and B(OH)₃) relative to Ca²⁺ and CO₃²⁻ that constitute the calcite lattice.

Original language	English
Pages (from-to)	67-82
Number of pages	16
Journal	Geochimica et Cosmochimica Acta
Volume	398
Early online date	26 Mar 2025
DOIs	https://doi.org/10.1016/j.gca.2025.03.022
Publication status	Published - 1 Jun 2025

Bibliographical note

Publisher Copyright:
© 2025 Elsevier Ltd

Funding

We thank Patrick Laan and Wim Boer for their assistance on E/Ca analyses and subsequent data processing. JU owes personal gratitude to Daniel Francois do Nascimento Silva and Karel Bakker during his visit to NIOZ and to Ms. Sandy Pieterse for housing. The samples utilized here were from Uchikawa et al. (2017), which was supported by U.S. National Science Foundation (NSF) awards OCE-1333357 and OCE-1536743 to JU and REZ. This study was supported by the funds received from the U.S. NSF (OCE-2024631, EAR-2001927, and OCE-2048436 to JU and REZ), the Netherlands Earth System Science Centre (Grant agreement #847504), and additionally from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant agreement #819588 to MW). We thank the feedback by Dr. Guillaume Paris and an anonymous reviewer that improved the clarity of the paper and Dr. Sambuddha Misra and Dr. Hailiang Dong for handling of our manuscript during the peer-review processes. We thank Patrick Laan and Wim Boer for their assistance on E/Ca analyses and subsequent data processing. JU owes personal gratitude to Daniel Francois do Nascimento Silva and Karel Bakker during his visit to NIOZ and to Ms. Sandy Pieterse for housing. The samples utilized here were from Uchikawa et al. (2017), which was supported by U.S. National Science Foundation (NSF) awards OCE-1333357 and OCE-1536743 to JU and REZ. This study was supported by the funds received from the U.S. NSF (OCE-2024631, EAR-2001927, and OCE-2048436 to JU and REZ), the Netherlands Earth System Science Centre, and additionally from the European Research Council (ERC) under the European Union\u2019s Horizon 2020 research and innovation programme (Grant agreement #819588 to MW). We thank the feedback by Dr. Guillaume Paris and an anonymous reviewer that improved the clarity of the paper and Dr. Sambuddha Misra and Dr. Hailiang Dong for handling of our manuscript during the peer-review processes.

Funders	Funder number
European Research Council
Horizon 2020
National Science Foundation	OCE-2048436, OCE-2024631, OCE-1333357, EAR-2001927, OCE-1536743
Netherlands Earth System Science Centre	847504
Horizon 2020 Framework Programme	819588

Keywords

Elemental incorporation
Inorganic calcite
Laboratory experiments
Paleo-proxies
Seawater chemistry

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10.1016/j.gca.2025.03.022

Changes in calcium ion concentration as the common driver for Na, K, S, and B incorporation during inorganic calcite precipitation in Mg-free artificial seawaterFinal published version, 4.95 MBLicence: Taverne

Cite this

Uchikawa, J., Karancz, S., Wolthers, M., Pacho, L., Harper, D. T., Penman, D. E., de Nooijer, L. J., Reichart, G.-J., & Zeebe, R. E. (2025). Changes in calcium ion concentration as the common driver for Na, K, S, and B incorporation during inorganic calcite precipitation in Mg-free artificial seawater. Geochimica et Cosmochimica Acta, 398, 67-82. https://doi.org/10.1016/j.gca.2025.03.022

@article{d428505cd2ca42948a255e9645477564,

title = "Changes in calcium ion concentration as the common driver for Na, K, S, and B incorporation during inorganic calcite precipitation in Mg-free artificial seawater",

abstract = "Calcite is known to incorporate a range of non-constituent ions during its precipitation from aqueous solutions. Their concentrations (measured as E/Ca ratios, where E denotes the elemental forms of non-constituent ions) in calcite formed in seawater can serve as useful tools for paleoceanographic studies. But this requires concrete understanding of the incorporation patterns and their dependence to environmental factors at the time of mineral precipitation. Here, we present Na/Ca, K/Ca, S/Ca, and B/Ca ratios of inorganic calcite samples generated in laboratory experiments using Mg-free artificial seawater with systematic manipulations of pH, [DIC], and [Ca2+]. The three parameters were varied both individually (the pH, DIC, and Ca experimental series) and in tandem (the pH-Ca and DIC-Ca series) to form calcites under variable versus near-constant precipitation rates (denoted as R). All measured E/Ca ratios showed a robust positive linear dependence to changes in [Ca2+] in the Ca, pH-Ca, and DIC-Ca series, irrespective of changes in R. While K/Ca and S/Ca ratios changed almost exclusively with [Ca2+], Na/Ca and B/Ca ratios showed an additionally strong increase with increasing pH and a more moderate increase with rising [DIC], when R changed accordingly in the pH and DIC series. While R-driven kinetic effects and/or formation of certain cation–anion pairs may be important for the elemental uptake in calcite under some circumstances, these mechanisms or processes cannot fully account for the observed trends in every experimental series for all E/Ca ratios considered here. We propose that the observed E/Ca trends can be comprehensively explained by simultaneously considering the nonequivalent influence of changes in solution [Ca2+] and [CO32−] on step-specific kink formation dynamics and the size difference between the respective non-constituent ions (K+, Na+, SO42−, and B(OH)4− and B(OH)3) relative to Ca2+ and CO32− that constitute the calcite lattice.",

keywords = "Elemental incorporation, Inorganic calcite, Laboratory experiments, Paleo-proxies, Seawater chemistry",

author = "Joji Uchikawa and Szabina Karancz and Mari{\"e}tte Wolthers and Laura Pacho and Harper, \{Dustin T.\} and Penman, \{Donald E.\} and \{de Nooijer\}, \{Lennart J.\} and Gert-Jan Reichart and Zeebe, \{Richard E.\}",

note = "Publisher Copyright: {\textcopyright} 2025 Elsevier Ltd",

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month = jun,

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doi = "10.1016/j.gca.2025.03.022",

language = "English",

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Uchikawa, J, Karancz, S, Wolthers, M, Pacho, L, Harper, DT, Penman, DE, de Nooijer, LJ, Reichart, G-J & Zeebe, RE 2025, 'Changes in calcium ion concentration as the common driver for Na, K, S, and B incorporation during inorganic calcite precipitation in Mg-free artificial seawater', Geochimica et Cosmochimica Acta, vol. 398, pp. 67-82. https://doi.org/10.1016/j.gca.2025.03.022

Changes in calcium ion concentration as the common driver for Na, K, S, and B incorporation during inorganic calcite precipitation in Mg-free artificial seawater. / Uchikawa, Joji; Karancz, Szabina; Wolthers, Mariëtte et al.
In: Geochimica et Cosmochimica Acta, Vol. 398, 01.06.2025, p. 67-82.

Research output: Contribution to journal › Article › Academic › peer-review

TY - JOUR

T1 - Changes in calcium ion concentration as the common driver for Na, K, S, and B incorporation during inorganic calcite precipitation in Mg-free artificial seawater

AU - Uchikawa, Joji

AU - Karancz, Szabina

AU - Wolthers, Mariëtte

AU - Pacho, Laura

AU - Harper, Dustin T.

AU - Penman, Donald E.

AU - de Nooijer, Lennart J.

AU - Reichart, Gert-Jan

AU - Zeebe, Richard E.

PY - 2025/6/1

Y1 - 2025/6/1

N2 - Calcite is known to incorporate a range of non-constituent ions during its precipitation from aqueous solutions. Their concentrations (measured as E/Ca ratios, where E denotes the elemental forms of non-constituent ions) in calcite formed in seawater can serve as useful tools for paleoceanographic studies. But this requires concrete understanding of the incorporation patterns and their dependence to environmental factors at the time of mineral precipitation. Here, we present Na/Ca, K/Ca, S/Ca, and B/Ca ratios of inorganic calcite samples generated in laboratory experiments using Mg-free artificial seawater with systematic manipulations of pH, [DIC], and [Ca2+]. The three parameters were varied both individually (the pH, DIC, and Ca experimental series) and in tandem (the pH-Ca and DIC-Ca series) to form calcites under variable versus near-constant precipitation rates (denoted as R). All measured E/Ca ratios showed a robust positive linear dependence to changes in [Ca2+] in the Ca, pH-Ca, and DIC-Ca series, irrespective of changes in R. While K/Ca and S/Ca ratios changed almost exclusively with [Ca2+], Na/Ca and B/Ca ratios showed an additionally strong increase with increasing pH and a more moderate increase with rising [DIC], when R changed accordingly in the pH and DIC series. While R-driven kinetic effects and/or formation of certain cation–anion pairs may be important for the elemental uptake in calcite under some circumstances, these mechanisms or processes cannot fully account for the observed trends in every experimental series for all E/Ca ratios considered here. We propose that the observed E/Ca trends can be comprehensively explained by simultaneously considering the nonequivalent influence of changes in solution [Ca2+] and [CO32−] on step-specific kink formation dynamics and the size difference between the respective non-constituent ions (K+, Na+, SO42−, and B(OH)4− and B(OH)3) relative to Ca2+ and CO32− that constitute the calcite lattice.

AB - Calcite is known to incorporate a range of non-constituent ions during its precipitation from aqueous solutions. Their concentrations (measured as E/Ca ratios, where E denotes the elemental forms of non-constituent ions) in calcite formed in seawater can serve as useful tools for paleoceanographic studies. But this requires concrete understanding of the incorporation patterns and their dependence to environmental factors at the time of mineral precipitation. Here, we present Na/Ca, K/Ca, S/Ca, and B/Ca ratios of inorganic calcite samples generated in laboratory experiments using Mg-free artificial seawater with systematic manipulations of pH, [DIC], and [Ca2+]. The three parameters were varied both individually (the pH, DIC, and Ca experimental series) and in tandem (the pH-Ca and DIC-Ca series) to form calcites under variable versus near-constant precipitation rates (denoted as R). All measured E/Ca ratios showed a robust positive linear dependence to changes in [Ca2+] in the Ca, pH-Ca, and DIC-Ca series, irrespective of changes in R. While K/Ca and S/Ca ratios changed almost exclusively with [Ca2+], Na/Ca and B/Ca ratios showed an additionally strong increase with increasing pH and a more moderate increase with rising [DIC], when R changed accordingly in the pH and DIC series. While R-driven kinetic effects and/or formation of certain cation–anion pairs may be important for the elemental uptake in calcite under some circumstances, these mechanisms or processes cannot fully account for the observed trends in every experimental series for all E/Ca ratios considered here. We propose that the observed E/Ca trends can be comprehensively explained by simultaneously considering the nonequivalent influence of changes in solution [Ca2+] and [CO32−] on step-specific kink formation dynamics and the size difference between the respective non-constituent ions (K+, Na+, SO42−, and B(OH)4− and B(OH)3) relative to Ca2+ and CO32− that constitute the calcite lattice.

KW - Elemental incorporation

KW - Inorganic calcite

KW - Laboratory experiments

KW - Paleo-proxies

KW - Seawater chemistry

UR - https://www.scopus.com/pages/publications/105002228425

U2 - 10.1016/j.gca.2025.03.022

DO - 10.1016/j.gca.2025.03.022

M3 - Article

SN - 0016-7037

VL - 398

SP - 67

EP - 82

JO - Geochimica et Cosmochimica Acta

JF - Geochimica et Cosmochimica Acta

ER -

Changes in calcium ion concentration as the common driver for Na, K, S, and B incorporation during inorganic calcite precipitation in Mg-free artificial seawater

Abstract

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Keywords

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