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The relationship between the ratio of strontium to calcium and sea-surface temperature in a modern Porites astreoides coral: Implications for using P. astreoides as a paleoclimate archive

November 13, 2015

An inverse relationship has been demonstrated between water temperature and the ratio of strontium to calcium (Sr/Ca) in coral aragonite for a number of Pacific species of the genus Porites. This empirically determined relationship has been used to reconstruct past sea-surface temperature (SST) from modern and Holocene age coral archives. A study was conducted to investigate this relationship for Porites astreoides to determine the potential for using these corals as a paleotemperature archive in the Caribbean and western tropical Atlantic Ocean. Skeletal aragonite from a P. astreoides colony growing offshore of the southeast coast of Florida was subsampled with a mean temporal resolution of 14 samples per year and analyzed for Sr/Ca. The resulting Sr/Ca time series yielded well-defined annual cycles that correspond to annual growth bands in the coral. Sr/Ca was regressed against a monthly SST record from C-MAN buoy station FWYF1 (located at Fowey Rocks, Florida), resulting in the following Sr/Ca-SST relationship: Sr/Ca = –0.040*SST + 10.128 (R = –0.77). A 10-year time series of Sr/Ca-derived SST yields annual cycles with a 10–12 degree Celsius seasonal amplitude, consistent with available local instrumental records. We conclude that Sr/Ca in Porites astreoides from the Caribbean/Atlantic region has high potential for developing subannually resolved modern and recent Holocene SST records.

Citation Information

Publication Year 2015
Title The relationship between the ratio of strontium to calcium and sea-surface temperature in a modern <i>Porites astreoides</i> coral: Implications for using <i>P. astreoides</i> as a paleoclimate archive
DOI 10.3133/ofr20151182
Authors Tess E. Busch, Jennifer A. Flannery, Julie N. Richey, Anastasios Stathakopoulos
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 2015-1182
Index ID ofr20151182
Record Source USGS Publications Warehouse
USGS Organization St. Petersburg Coastal and Marine Science Center