The dissolution behavior of biogenic calcites in seawater and a possible role for magnesium and organic carbon
We present the dissolution kinetics of mixed planktic foraminifera, the benthic foraminifera Amphistegina, the coccolithophore Emiliania huxleyi, and the soft coral Rhythismia fulvum in seawater. Dissolution rates were measured across a large range of saturation states (Ω = 0.99–0.2) by disso...
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ftcaltechauth:oai:authors.library.caltech.edu:5vnt4-rcb54 2024-06-23T07:55:50+00:00 The dissolution behavior of biogenic calcites in seawater and a possible role for magnesium and organic carbon Subhas, Adam V. Rollins, Nick E. Berelson, William M. Erez, Jonathan Ziveri, Patrizia Langer, Gerald Adkins, Jess F. 2018-09-20 https://doi.org/10.1016/j.marchem.2018.08.001 unknown Elsevier https://doi.org/10.1016/j.marchem.2018.08.001 oai:authors.library.caltech.edu:5vnt4-rcb54 eprintid:88790 resolverid:CaltechAUTHORS:20180813-154925391 info:eu-repo/semantics/closedAccess Other Marine Chemistry, 205, 100-112, (2018-09-20) Chemical oceanography Dissolution kinetics Ocean acidification info:eu-repo/semantics/article 2018 ftcaltechauth https://doi.org/10.1016/j.marchem.2018.08.001 2024-06-12T06:27:06Z We present the dissolution kinetics of mixed planktic foraminifera, the benthic foraminifera Amphistegina, the coccolithophore Emiliania huxleyi, and the soft coral Rhythismia fulvum in seawater. Dissolution rates were measured across a large range of saturation states (Ω = 0.99–0.2) by dissolving ^(13)C-labeled calcites in natural seawater undersaturated with respect to calcite. ^(13)C-label was incorporated into biogenic calcite by culturing marine calcifiers in 13C-labeled natural seawater. Net dissolution rates were calculated as the slope of seawater δ^(13)C versus time in a closed seawater-calcite system. All calcites show distinct, nonlinear, dependencies on seawater saturation state when normalized by mass or by specific surface area. For example, coccolith calcite dissolves at a similar rate to inorganic calcite near equilibrium when normalized by surface area, but dissolves much more slowly far from equilibrium. Mass loss from foraminiferal tests is correlated with a decrease in Mg/Ca of the solid, indicating that Mg-rich phases are preferentially leached out at even mild undersaturations. Dissolution also appears to strongly affect test B/Ca. Finally, we provide an interpretation of surface area-normalized biogenic calcite dissolution rates as a function of their Mg and organic carbon content. Near-equilibrium dissolution rates of all calcites measured here show a strong, nonlinear dependence on Mg content. Far-from-equilibrium dissolution rates decrease strongly as a function of organic carbon content. These results help to build a framework for understanding the underlying mechanisms of rate differences between biogenic calcites, and bear important implications for the dissolution of high-Mg calcites in view of ocean acidification. © 2018 Elsevier B.V. Received 13 February 2018, Revised 25 July 2018, Accepted 2 August 2018, Available online 12 August 2018. Article in Journal/Newspaper Ocean acidification Caltech Authors (California Institute of Technology) Marine Chemistry 205 100 112 |
institution |
Open Polar |
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Caltech Authors (California Institute of Technology) |
op_collection_id |
ftcaltechauth |
language |
unknown |
topic |
Chemical oceanography Dissolution kinetics Ocean acidification |
spellingShingle |
Chemical oceanography Dissolution kinetics Ocean acidification Subhas, Adam V. Rollins, Nick E. Berelson, William M. Erez, Jonathan Ziveri, Patrizia Langer, Gerald Adkins, Jess F. The dissolution behavior of biogenic calcites in seawater and a possible role for magnesium and organic carbon |
topic_facet |
Chemical oceanography Dissolution kinetics Ocean acidification |
description |
We present the dissolution kinetics of mixed planktic foraminifera, the benthic foraminifera Amphistegina, the coccolithophore Emiliania huxleyi, and the soft coral Rhythismia fulvum in seawater. Dissolution rates were measured across a large range of saturation states (Ω = 0.99–0.2) by dissolving ^(13)C-labeled calcites in natural seawater undersaturated with respect to calcite. ^(13)C-label was incorporated into biogenic calcite by culturing marine calcifiers in 13C-labeled natural seawater. Net dissolution rates were calculated as the slope of seawater δ^(13)C versus time in a closed seawater-calcite system. All calcites show distinct, nonlinear, dependencies on seawater saturation state when normalized by mass or by specific surface area. For example, coccolith calcite dissolves at a similar rate to inorganic calcite near equilibrium when normalized by surface area, but dissolves much more slowly far from equilibrium. Mass loss from foraminiferal tests is correlated with a decrease in Mg/Ca of the solid, indicating that Mg-rich phases are preferentially leached out at even mild undersaturations. Dissolution also appears to strongly affect test B/Ca. Finally, we provide an interpretation of surface area-normalized biogenic calcite dissolution rates as a function of their Mg and organic carbon content. Near-equilibrium dissolution rates of all calcites measured here show a strong, nonlinear dependence on Mg content. Far-from-equilibrium dissolution rates decrease strongly as a function of organic carbon content. These results help to build a framework for understanding the underlying mechanisms of rate differences between biogenic calcites, and bear important implications for the dissolution of high-Mg calcites in view of ocean acidification. © 2018 Elsevier B.V. Received 13 February 2018, Revised 25 July 2018, Accepted 2 August 2018, Available online 12 August 2018. |
format |
Article in Journal/Newspaper |
author |
Subhas, Adam V. Rollins, Nick E. Berelson, William M. Erez, Jonathan Ziveri, Patrizia Langer, Gerald Adkins, Jess F. |
author_facet |
Subhas, Adam V. Rollins, Nick E. Berelson, William M. Erez, Jonathan Ziveri, Patrizia Langer, Gerald Adkins, Jess F. |
author_sort |
Subhas, Adam V. |
title |
The dissolution behavior of biogenic calcites in seawater and a possible role for magnesium and organic carbon |
title_short |
The dissolution behavior of biogenic calcites in seawater and a possible role for magnesium and organic carbon |
title_full |
The dissolution behavior of biogenic calcites in seawater and a possible role for magnesium and organic carbon |
title_fullStr |
The dissolution behavior of biogenic calcites in seawater and a possible role for magnesium and organic carbon |
title_full_unstemmed |
The dissolution behavior of biogenic calcites in seawater and a possible role for magnesium and organic carbon |
title_sort |
dissolution behavior of biogenic calcites in seawater and a possible role for magnesium and organic carbon |
publisher |
Elsevier |
publishDate |
2018 |
url |
https://doi.org/10.1016/j.marchem.2018.08.001 |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
Marine Chemistry, 205, 100-112, (2018-09-20) |
op_relation |
https://doi.org/10.1016/j.marchem.2018.08.001 oai:authors.library.caltech.edu:5vnt4-rcb54 eprintid:88790 resolverid:CaltechAUTHORS:20180813-154925391 |
op_rights |
info:eu-repo/semantics/closedAccess Other |
op_doi |
https://doi.org/10.1016/j.marchem.2018.08.001 |
container_title |
Marine Chemistry |
container_volume |
205 |
container_start_page |
100 |
op_container_end_page |
112 |
_version_ |
1802648581520228352 |