Interpreting sea surface temperature from strontium/calcium ratios in Montastrea corals : link with growth rate and implications for proxy reconstructions
Saenger, Casey P.
Cohen, Anne L.
Oppo, Delia W.
MetadataShow full item record
We analyzed strontium/calcium ratios (Sr/Ca) in four colonies of the Atlantic coral genus Montastrea with growth rates ranging from 2.3 to 12.6 mm a−1. Derived Sr/Ca–sea surface temperature (SST) calibrations exhibit significant differences among the four colonies that cannot be explained by variations in SST or seawater Sr/Ca. For a single coral Sr/Ca ratio of 8.8 mmol mol−1, the four calibrations predict SSTs ranging from 24.0° to 30.9°C. We find that differences in the Sr/Ca–SST relationships are correlated systematically with the average annual extension rate (ext) of each colony such that Sr/Ca (mmol mol−1) = 11.82 (±0.13) – 0.058 (±0.004) × ext (mm a−1) – 0.092 (±0.005) × SST (°C). This observation is consistent with previous reports of a link between coral Sr/Ca and growth rate. Verification of our growth-dependent Sr/Ca–SST calibration using a coral excluded from the calibration reconstructs the mean and seasonal amplitude of the actual recorded SST to within 0.3°C. Applying a traditional, nongrowth-dependent Sr/Ca–SST calibration derived from a modern Montastrea to the Sr/Ca ratios of a conspecific coral that grew during the early Little Ice Age (LIA) (400 years B.P.) suggests that Caribbean SSTs were >5°C cooler than today. Conversely, application of our growth-dependent Sr/Ca–SST calibration to Sr/Ca ratios derived from the LIA coral indicates that SSTs during the 5-year period analyzed were within error (±1.4°C) of modern values.
Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 23 (2008): PA3102, doi:10.1029/2007PA001572.
Showing items related by title, author, creator and subject.
Holcomb, Michael; Cohen, Anne L.; McCorkle, Daniel C. (2012-12)In situ skeletal markers have been widely used to quantify skeletal growth rates of scleractinian corals on sub-annual time-scales. Nevertheless, an evaluation of different techniques, both in terms of their efficacy and ...
Temporal variation in the symbiosis and growth of the temperate scleractinian coral Astrangia poculata Dimond, Jay; Carrington, Emily (Inter-Research, 2007-10-25)Seasonal variation in the algal symbiosis and growth of Astrangia poculata, a facultatively symbiotic temperate scleractinian, was explored in Rhode Island, USA. Coral pigmentation and growth were measured simultaneously ...
Bosshart, Sara A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2013-02)Accurate predictions of Caribbean carol reef responses to global climate change are currently limited by a lack of knowledge of the dominant environmental controls on coral growth. Corals exhibit significant responses to ...