Climate of the Past
Climate of the Past
CP
Articles | Volume 11, issue 3
Articles | Volume 11, issue 3
https://doi.org/10.5194/cp-11-523-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/cp-11-523-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Articles | Volume 11, issue 3
Research article
 | 
24 Mar 2015
Research article |  | 24 Mar 2015

Evidence for the non-influence of salinity variability on the Porites coral Sr/Ca palaeothermometer

M. Moreau, T. Corrège, E. P. Dassié, and F. Le Cornec

Abstract. Porites coral-based sea surface temperature (SST) reconstructions are obtained from the measurement of skeleton Sr/Ca ratio. However, the influence of salinity in the incorporation of these trace elements in the Porites aragonitic skeleton is still poorly documented. Laboratory experiments indicate that in three different coral species (not including the widely used Porites genus), salinity does not influence the Sr/Ca thermometer. In this study, we test the salinity effect on Porites Sr/Ca-based SST reconstructions at monthly and interannual timescales in open-ocean environmental conditions. We use a large spatial compilation of published Porites data from the Red Sea and Pacific and Indian oceans. Additionally to those published records, we add a new eastern Pacific coral Sr/Ca record from Clipperton Atoll.

Using two different salinity products (Simple Ocean Data Assimilation (SODA) SSS reanalyses version 2.2.4, Carton and Giese, 2008; and instrumental SSS from the Institut de Recherche pour le Développement, France (IRD) Delcroix et al., 2011), we find no evidence of salinity bias on the Sr/Ca SST proxy at monthly and interannual timescales. We conclude that Porites Sr/Ca is a reliable palaeothermometer that is not influenced by salinity variability.

How to cite. Moreau, M., Corrège, T., Dassié, E. P., and Le Cornec, F.: Evidence for the non-influence of salinity variability on the Porites coral Sr/Ca palaeothermometer, Clim. Past, 11, 523–532, https://doi.org/10.5194/cp-11-523-2015, 2015.
Received: 21 Mar 2014 – Discussion started: 14 Apr 2014 – Revised: 19 Feb 2015 – Accepted: 23 Feb 2015 – Published: 24 Mar 2015
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Short summary
The influence of salinity on the Porites Sr/Ca palaeothermometer is still poorly documented. We test the salinity effect on Porites Sr/Ca-based SST reconstructions using a large spatial compilation of published Porites data from the Pacific, Indian Ocean, and the Red Sea. We find no evidence of a salinity bias in the Sr/Ca SST proxy at monthly and interannual timescales using two different salinity products. This result is in agreement with laboratory experiments on coral species.
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