B content and Si/C ratios from cultured diatoms (Thalassiosira pseudonana and Thalassiosira weissflogii) : relationship to seawater pH and diatom carbon acquisition

dc.contributor.author Mejia, Luz Maria
dc.contributor.author Isensee, Kirsten
dc.contributor.author Mendez-Vicente, Ana
dc.contributor.author Pisonero, Jorge
dc.contributor.author Shimizu, Nobumichi
dc.contributor.author Gonzalez, Cristina
dc.contributor.author Monteleone, Brian D.
dc.contributor.author Stoll, Heather M.
dc.date.accessioned 2013-12-16T20:33:39Z
dc.date.available 2013-12-16T20:33:39Z
dc.date.issued 2013-06-18
dc.description © The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geochimica et Cosmochimica Acta 123 (2013): 322–337, doi:10.1016/j.gca.2013.06.011. en_US
dc.description.abstract Despite the importance of diatoms in regulating climate and the existence of large opal-containing sediments in key air-ocean exchange areas, most geochemical proxy records are based on carbonates. Among them, Boron (B) content and isotopic composition have been widely used to reconstruct pH from foraminifera and coral fossils. We assessed the possibility of a pH/CO2 seawater concentration control on B content in diatom opal to determine whether or not frustule B concentrations could be used as a pH proxy or to clarify algae physiological responses to acidifying pH. We cultured two well-studied diatom species, Thalassiosira pseudonana and Thalassiosira weissflogii at varying pH conditions and determined Si and C quotas. Frustule B content was measured by both laser-ablation inductively coupled mass spectrometry (LA-ICPMS) and secondary ion mass spectrometry (SIMS/ion probe). For both species, frustules grown at higher pH have higher B contents and higher Si requirements per fixed C. If this trend is representative of diatom silicification in a future more acidic ocean, it could contribute to changes in the efficiency of diatom ballasting and C export, as well as changes in the contribution of diatoms relative to other phytoplankton groups in Si-limited regions. If B enters the cell through the same transporter employed for HCO3− uptake, an increased HCO3− requirement with decreasing CO2 concentrations (higher pH), and higher B(OH)4/HCO3− ratios would explain the observed increase in frustule B content with increasing pH. The mechanism of B transport from the site of uptake to the site of silica deposition is unknown, but may occur via silicon transport vesicles, in which B(OH)4− may be imported for B detoxification and/or as part of a pH regulation strategy either though Na-dependent B(OH)4−/Cl− antiport or B(OH)4−/H+ antiport. B deposition in the silica matrix may occur via substitution of a B(OH)4− for a negatively charged SiO− formed during silicification. With the current analytical precision, B content of frustules is unlikely to resolve ocean pH with a precision of paleoceanographic interest. However, if frustule B content was controlled mainly by HCO3− uptake for photosynthesis, which appears to show a threshold behavior, then measurements of B content might reveal the varying importance of active HCO3− acquisition mechanisms of diatoms in the past. en_US
dc.description.sponsorship This work was funded by the European Community under the project ERC-STG-240222-PACE. en_US
dc.format.mimetype application/pdf
dc.identifier.citation Geochimica et Cosmochimica Acta 123 (2013): 322–337 en_US
dc.identifier.doi 10.1016/j.gca.2013.06.011
dc.identifier.uri https://hdl.handle.net/1912/6351
dc.language.iso en en_US
dc.publisher Elsevier en_US
dc.relation.uri https://doi.org/10.1016/j.gca.2013.06.011
dc.rights Attribution-NonCommercial-NoDerivs 3.0 Unported *
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/ *
dc.title B content and Si/C ratios from cultured diatoms (Thalassiosira pseudonana and Thalassiosira weissflogii) : relationship to seawater pH and diatom carbon acquisition en_US
dc.type Article en_US
dspace.entity.type Publication
relation.isAuthorOfPublication 1c6de8a3-8d90-46d7-8685-02df4cc3f072
relation.isAuthorOfPublication b9a1688e-5fcb-4235-b223-278f58bdf89c
relation.isAuthorOfPublication a90084bc-7a65-4619-b0b5-5313f7add072
relation.isAuthorOfPublication 50fabba3-cfba-4a7e-be04-02d724198d3f
relation.isAuthorOfPublication 3e817505-8f0c-4654-97b9-e52c53d64153
relation.isAuthorOfPublication d46adfdc-a4a5-442c-a698-b544f920fa03
relation.isAuthorOfPublication aad1c7b1-8433-484d-8a26-4fffd854c4c8
relation.isAuthorOfPublication d3de0363-b804-47f0-a185-83c4b3f17e5d
relation.isAuthorOfPublication.latestForDiscovery 1c6de8a3-8d90-46d7-8685-02df4cc3f072
Original bundle
Now showing 1 - 2 of 2
Thumbnail Image
458.45 KB
Adobe Portable Document Format
Thumbnail Image
403.38 KB
Adobe Portable Document Format
Supplementary data
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
1.89 KB
Item-specific license agreed upon to submission