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An Atomic Force Microscopy Study of Calcite Dissolution in Seawater

Dong, Sijia and Berelson, William M. and Adkins, Jess F. and Rollins, Nick E. and Naviaux, John D. and Pirbadian, Sahand and El-Naggar, Mohamed Y. and Teng, H. Henry (2020) An Atomic Force Microscopy Study of Calcite Dissolution in Seawater. Geochimica et Cosmochimica Acta, 283 . pp. 40-53. ISSN 0016-7037. https://resolver.caltech.edu/CaltechAUTHORS:20200609-071637828

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Abstract

We present the first examination of calcite dissolution in seawater using Atomic Force Microscopy (AFM). We quantify step retreat velocity and etch pit density to compare dissolution in seawater to low ionic strength water, and also to compare calcite dissolution under AFM conditions to those conducted in bulk solution experiments (e.g. Subhas et al., 2015, Dong et al., 2018). Bulk dissolution rates and step retreat velocities are slower at high and mid-saturation state (Ω) values and become comparable to low ionic strength water rates at low Ω. The onset of defect-assisted etch pit formation in seawater is at Ω ∼ 0.85 (defined as Ω_(critical)), higher than in low ionic strength water (Ω ∼ 0.54). There is an abrupt increase in etch pit density (from ∼10⁶ cm⁻² to ∼10⁸ cm⁻²) occurring when Ω falls below 0.7 in seawater, compared to Ω ∼ 0.1 in low ionic strength water, suggesting a transition from defect-assisted dissolution to homogeneous dissolution much closer to equilibrium in seawater. The step retreat velocity (v) does not scale linearly with undersaturation (1-Ω) across an Ω range of 0.4 to 0.9 in seawater, potentially indicating a high order correlation between kink rate and Ω for non-Kossel crystals such as calcite, or surface complexation processes during calcite dissolution in seawater.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.gca.2020.05.031DOIArticle
ORCID:
AuthorORCID
Dong, Sijia0000-0002-5811-9333
Adkins, Jess F.0000-0002-3174-5190
Additional Information:© 2020 Elsevier Ltd. Received 8 November 2019, Revised 27 May 2020, Accepted 28 May 2020, Available online 6 June 2020. This work was supported by NSF Ocean Acidification grants (numbers OCE1220600 and OCE1220302), USC Dornsife Doctoral Fellowship, and Grantham Foundation at Caltech. The authors would like to thank four anonymous journal reviewers, as well as the associate editor Dr. Oleg Pokrovsky, for their insightful comments and suggestions that helped to improve this manuscript. We thank Mina Hong, Zibo Li and Liang Zhao for helpful discussions on AFM operations. We also thank Josh West for his suggestions on the manuscript. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Funders:
Funding AgencyGrant Number
NSFOCE-1220600
NSFOCE-1220302
University of Southern CaliforniaUNSPECIFIED
Grantham FoundationUNSPECIFIED
Record Number:CaltechAUTHORS:20200609-071637828
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200609-071637828
Official Citation:Sijia Dong, William M. Berelson, Jess F. Adkins, Nick E. Rollins, John D. Naviaux, Sahand Pirbadian, Mohamed Y. El-Naggar, H. Henry Teng, An atomic force microscopy study of calcite dissolution in seawater, Geochimica et Cosmochimica Acta, Volume 283, 2020, Pages 40-53, ISSN 0016-7037, https://doi.org/10.1016/j.gca.2020.05.031. (http://www.sciencedirect.com/science/article/pii/S0016703720303586)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103781
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 Jun 2020 14:37
Last Modified:26 Jun 2020 17:19

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