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

Tess E. Busch; Jennifer A. Flannery; Julie N. Richey; Anastasios Stathakopoulos

doi:10.3133/ofr20151182

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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

Tess E. Busch·Jennifer A. Flannery·Julie N. Richey·Anastasios Stathakopoulos

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Abstract

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.

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Source-reported bounding extent: 24.956180020055925° to 27.756468889550746° latitude; -82.99621582031249° to -79.38720703125° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Tess E. Busch, Jennifer A. Flannery, Julie N. Richey, Anastasios Stathakopoulos. 2015-11-13. 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. https://doi.org/10.3133/ofr20151182

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