EGU21-13949, updated on 19 May 2023
EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Assessing the impact of Sr/Ca-SST calibrations on coral-based seawater δ18O reconstructions - First results from PAGES CoralHydro2k

Rachel Walter1 and the PAGES CoralHydro2k*
Rachel Walter and the PAGES CoralHydro2k
  • 1School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, United States of America
  • *A full list of authors appears at the end of the abstract

Corals are distributed throughout the tropical oceans, making them useful for resolving climate information covering time before the satellite era when instrumental data is often scarce. Coral δ18O has been used to reconstruct changes in both sea surface temperature (SST) and hydrology, while coral Sr/Ca is thought to mainly record SST. Coral δ18O data, when used in conjunction with Sr/Ca, can therefore be used to reconstruct seawater δ18O (δ18Osw), an indicator of the local precipitation-evaporation balance as well as other surface ocean hydrological changes. Coral Sr/Ca-SST relationships are critical for reconstructing δ18Osw from paired Sr/Ca and δ18O records, but vary across existing literature. Some of this variation is due to existing natural differences between corals, but variation also stems from differences in calibration methods or SST products used to determine the Sr/Ca-SST relationship. Such methodological differences complicate the comparison of results across studies and slow efforts to create a global picture of reconstructed tropical ocean hydroclimate.

Here, we use the PAGES CoralHydro2k database - a collection of 45 paired coral Sr/Ca-δ18O records and 70 coral δ18O records - to assess different methodological choices such as SST product and regression method and develop a calibration framework to use as a set of “best practices” moving forward. We also examine the sensitivity of δ18Osw to our calibration framework and to existing δ18Osw calculation methods. The PAGES CoralHydro2k project aims to leverage its coral database and apply these best practices and insights to a global reconstruction of tropical marine hydrology over the past 200 years.

PAGES CoralHydro2k:

Hussein R. Sayani, Kim M. Cobb, Thomas Felis, Nerilie J. Abram, Matthew J. Fischer, Jessica Hargreaves, Alyssa Atwood, Logan Brenner, Emilie Dassié, Kristine DeLong, Bethany Ellis, Nathalie Goodkin, Nicholas Hitt, K. Halimeda Kilbourne, Hedwig Krawczyk, Belen Martrat, Sujata Murty, Ross Ong, Riovie Ramos, Emma Reed, Dhrubajyoti Samanta, Sara C. Sanchez, Feng Zhu, Jens Zinke

How to cite: Walter, R. and the PAGES CoralHydro2k: Assessing the impact of Sr/Ca-SST calibrations on coral-based seawater δ18O reconstructions - First results from PAGES CoralHydro2k, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13949,, 2021.

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