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dc.contributor.authorChen, Sang
dc.contributor.authorLittley, Eloise F. M.
dc.contributor.authorRae, James W. B.
dc.contributor.authorCharles, Christopher D.
dc.contributor.authorAdkins, Jess F.
dc.date.accessioned2021-04-08T10:30:26Z
dc.date.available2021-04-08T10:30:26Z
dc.date.issued2021-03-23
dc.identifier.citationChen , S , Littley , E F M , Rae , J W B , Charles , C D & Adkins , J F 2021 , ' Uranium distribution and incorporation mechanism in deep-sea corals : implications for seawater [CO 3 2– ] proxies ' , Frontiers in Earth Science , vol. 9 , 641327 . https://doi.org/10.3389/feart.2021.641327en
dc.identifier.issn2296-6463
dc.identifier.otherPURE: 273686787
dc.identifier.otherPURE UUID: 584811e0-063f-46eb-ab33-8bd5af43bca9
dc.identifier.otherJisc: 65fbb88a54ea44f38c4c62cde6237ced
dc.identifier.otherORCID: /0000-0003-3904-2526/work/92020065
dc.identifier.otherORCID: /0000-0003-1442-7585/work/92020165
dc.identifier.otherWOS: 000637004100001
dc.identifier.otherScopus: 85103756797
dc.identifier.urihttps://hdl.handle.net/10023/22983
dc.descriptionThis research received funding from NSF grant OCE-1737404 awarded to JA and China Scholarship Council Ph.D. Scholarship 201508020007 awarded to SC. JR was supported by ERC Starting Grant 805246 OldCO2NewArchives.en
dc.description.abstractA conservative element in seawater, uranium is readily incorporated into the aragonitic skeletons of scleractinian corals, making them an important paleoclimate archive that can be absolutely dated with U-Th techniques. In addition, uranium concentrations (U/Ca ratios) in corals have been suggested to be influenced by the temperature and/or carbonate ion concentration of the ambient seawater based on empirical calibrations. Microsampling techniques have revealed strong heterogeneities in U/Ca within individual specimens in both surface and deep-sea corals, suggesting a biological control on the U incorporation into the skeletons. Here we further explore the mechanism of uranium incorporation in coral skeletons with the deep-sea species Desmophyllum dianthus, an ideal test organism for the biomineralization processes due to its relatively constant growth environment. We find a negative correlation between bulk coral U/Ca and temperature as well as ambient pH and [CO32–] that is consistent with previous studies. By sampling the growth bands of individual corals, we also find a twofold change in U/Ca within individual corals that is strongly correlated with the δ18O, δ13C, and other Me/Ca ratios of the bands. A similar correlation between U/Ca and stable isotopes as well as other Me/Ca ratios are observed in bulk deep-sea coral samples. With a numerical coral calcification model, we interpret the U/Ca-stable isotope correlation as a result of changes in uranium speciation in response to internal pH elevations in the extracellular calcifying fluid (ECF) of the corals, and suggest that the Ca2UO2(CO3)3(aq) complex, the dominant U species in seawater, may be the major species incorporated into the coral skeleton. Therefore, the correlation between U/Ca and ambient [CO32–] is likely a result of the response of the biomineralization process, especially the magnitude of internal pH elevation, to the growth environment of the corals. Our data suggest overall lower alkalinity pump rates in corals from low saturation seawater compared to those from high saturation seawater, and possible increases in Ca2+ supply from active pumping relative to seawater transport in response to the environmental stress of low saturation.
dc.format.extent14
dc.language.isoeng
dc.relation.ispartofFrontiers in Earth Scienceen
dc.rightsCopyright © 2021 Chen, Littley, Rae, Charles and Adkins. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.en
dc.subjectDeep-sea coralsen
dc.subjectUraniumen
dc.subjectCarbonate ionen
dc.subjectBiomineralizationen
dc.subjectStable isotopesen
dc.subjectGE Environmental Sciencesen
dc.subjectDASen
dc.subject.lccGEen
dc.titleUranium distribution and incorporation mechanism in deep-sea corals : implications for seawater [CO32–] proxiesen
dc.typeJournal articleen
dc.contributor.sponsorNERCen
dc.contributor.sponsorEuropean Research Councilen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Earth & Environmental Sciencesen
dc.contributor.institutionUniversity of St Andrews. St Andrews Isotope Geochemistryen
dc.identifier.doihttps://doi.org/10.3389/feart.2021.641327
dc.description.statusPeer revieweden
dc.identifier.grantnumberNE/N003861/1en
dc.identifier.grantnumber805246en


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