Adriana Vélez-Galiano, University of Puerto Rico - Arecibo

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Abstract:

Reef-building corals are geochemical archives that allow reconstruction of temperature in marine environments over seasonal to centennial time scales. The strontium (Sr) to calcium (Ca) ratio of the coral skeleton is inversely related to the sea surface temperature (SST) in which the coral grows. Theoretically, seawater Sr/Ca variability can affect the accuracy of coral Sr/Ca paleothermometry, but most oceanographers assume Sr/Ca is near constant and seawater Sr/Ca measurements are often not made. In this study, I used seawater Sr/Ca and Siderastrea siderea and Diploria strigosa coral Sr/Ca data to investigate the impact of seawater Sr/Ca fluctuations in coral reef environments on coral Sr/Ca-based paleotemperature studies. The coral Sr/Ca and SST calibrations generally demonstrated an inverse linear regression, as expected from many prior calibrations. However, the regression slopes were not significantly different from zero when the coral Sr/Ca data were corrected for seawater Sr/Ca. Future work should use higher precision seawater analytical methods to avoid adding noise when correcting the coral Sr/Ca data.