Skip to content

Research at St Andrews

Uranium distribution and incorporation mechanism in deep-sea corals: implications for seawater [CO32–] proxies

Research output: Contribution to journalArticlepeer-review

Author(s)

Sang Chen, Eloise F. M. Littley, James W. B. Rae, Christopher D. Charles, Jess F. Adkins

School/Research organisations

Abstract

A 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.
Close

Details

Original languageEnglish
Article number641327
Number of pages14
JournalFrontiers in Earth Science
Volume9
DOIs
Publication statusPublished - 23 Mar 2021

    Research areas

  • Deep-sea corals, Uranium, Carbonate ion, Biomineralization, Stable isotopes

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. Interactions between deep formation fluid and gas hydrate dynamics inferred from pore fluid geochemistry at active pockmarks of the Vestnesa Ridge, west Svalbard margin

    Hong, W-L., Pape, T., Schmidt, C., Yao, H., Wallmann, K., Plaza-Faverola, A., Rae, J. W. B., Lepland, A., Bünz, S. & Bohrmann, G., May 2021, In: Marine and Petroleum Geology. 127, 13 p., 104957.

    Research output: Contribution to journalArticlepeer-review

  2. Atmospheric CO2 over the past 66 million years from marine archives

    Rae, J. W. B., Zhang, Y. G., Liu, X., Foster, G. L., Stoll, H. M. & Whiteford, R. D. M., May 2021, In: Annual Review of Earth and Planetary Sciences. 49, 1

    Research output: Contribution to journalArticlepeer-review

  3. Carbon cycle dynamics during episodes of rapid climate change

    Meissner, K. J., Brook, E., Finkelstein, S. A. & Rae, J., 23 Mar 2021, In: Environmental Research Letters. 16, 4, 8 p., 040201.

    Research output: Contribution to journalEditorialpeer-review

  4. Controls on boron isotopes in a cold-water coral and the cost of resilience to ocean acidification

    Gagnon, A., Gothmann, A., Branson, O., Rae, J. W. B. & Stewart, J., 15 Jan 2021, In: Earth and Planetary Science Letters. 554, 10 p., 116662.

    Research output: Contribution to journalArticlepeer-review

  5. Overturning circulation, nutrient limitation, and warming in the Glacial North Pacific

    Rae, J. W. B., Gray, W. R., Wills, R. C. J., Eisenman, I., Fitzhugh, B., Fotheringham, M., Littley, E., Rafter, P. A., Rees-Owen, R. L., Ridgwell, A., Taylor, B. & Burke, A., 9 Dec 2020, In: Science Advances. 6, 50, 13 p., eabd1654.

    Research output: Contribution to journalArticlepeer-review

Related by journal

  1. Marine sedimentary carbon stocks of the United Kingdom’s Exclusive Economic Zone

    Smeaton, C., Hunt, C. A., Turrell, W. & Austin, W., 4 Mar 2021, In: Frontiers in Earth Science. 9, 593324.

    Research output: Contribution to journalArticlepeer-review

  2. Reconstructing nitrogen sources to Earth’s earliest biosphere at 3.7 Ga

    Stüeken, E. E., Boocock, T., Szilas, K., Mikhail, S. & Gardiner, N. J., 30 Apr 2021, In: Frontiers in Earth Science. 9, 675726.

    Research output: Contribution to journalArticlepeer-review

  3. Early diagenetic imprint on temperature proxies in holocene corals: a case study from French Polynesia

    Rashid, R., Eisenhauer, A., Liebetrau, V., Fietzke, J., Böhm, F., Wall, M., Krause, S., Rüggeberg, A., Dullo, W-C., Jurikova, H., Samankassou, E. & Lazar, B., 22 Jul 2020, In: Frontiers in Earth Science. 8, 19 p., 301.

    Research output: Contribution to journalArticlepeer-review

  4. Editorial: deep carbon science

    Cardace, D., Bower, D., Daniel, I., Ionescu, A., Mikhail, S., Pistone, M. & Zahirovic, S., 12 Nov 2020, In: Frontiers in Earth Science. 8, 611295.

    Research output: Contribution to journalEditorialpeer-review

ID: 273686787

Top