Sea surface temperature and salinity variability at Bermuda during the end of the Little Ice Age

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Figure S1: Wintertime sea surface temperatures from Hydrostation S and wintertime Sr/Ca measurements from 1976 to 1997 shown both versus time and one another. (980.2Kb)

Figure S2: Wintertime sea surface temperatures from HadISST and wintertime Sr/Ca measurements from 1870 to 1997 shown versus time both annually and in five-year averages and versus one another. (1.071Mb)

Figure S3: Five-year averaged wintertime Sr/Ca and five-year averaged Sr/Ca-based reconstructed sea surface temperature over the full multicentury record. (1.041Mb)

Figure S4: Monthly coral δ18O versus sea surface temperature, salinity, and Sr/Ca. (1.123Mb)

Figure S5: Mean-annual coral δ18O versus Hydrostation S sea surface temperature, coral δ18O versus sea water δ18O generated from Hydrostation s data, reconstructed coral δ18O versus measured coral δ18O, and reconstructed sea water δ18O versus calculated δ18O. (1.401Mb)

Figure S6: Mean-annual coral δ18O minus Hydrostation S generated water δ18O versus Hydrostation S sea surface temperature, reconstructed coral δ18O minus water δ18O versus coral δ18O minus Hydrostation S generated water δ18O, reconstructed coral δ18O versus measured coral δ18O, and reconstructed water δ180 versus Hydrostation S generated water δ18O. (1.440Mb)

Figure S7: Mean-annual coral δ18O, coral reconstructed sea surface temperature, reconstructed sea water δ18O using equation (B2), and reconstructed sea water δ18O using equation (B3) all versus time. (1.729Mb)

Figure S8: Wintertime coral δ18O versus Hydrostation S sea surface temperature, coral δ18O versus sea water δ18O generated from Hydrostation s data, reconstructed coral δ18O versus measured coral δ18O, and reconstructed sea water δ18O versus calculated δ18O. (1.412Mb)

Figure S9: Wintertime coral δ18O minus Hydrostation S generated water δ18O versus Hydrostation S sea surface temperature, reconstructed coral δ18O minus water δ18O versus coral δ18O minus Hydrostation S generated water δ18O, reconstructed coral δ18O versus measured coral δ18O, and reconstructed water δ180 versus Hydrostation S generated water δ18O. (1.436Mb)

Figure S10: Wintertime coral δ18O, coral reconstructed sea surface temperature, reconstructed sea water δ18O using equation (B4), and reconstructed sea water δ18O using equation (B5) all versus time. (1.831Mb)

Additional file information (4.572Kb)

Table S1: Results of the wintertime regressions of Sr/Ca to SST. (764.3Kb)

Table S1: Results of the wintertime regressions of Sr/Ca to SST. (613bytes)

Text S1: Wintertime Sr/Ca–SST calibration. (6.308Kb)

Text S2: Quantitative relationships of coral δ18O to sea surface temperature and salinity. (17.37Kb)

Date

2008-07-09

Author

Goodkin, Nathalie F.

Hughen, Konrad A.

Curry, William B.

Doney, Scott C.

Ostermann, Dorinda R.

Metadata

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Citable URI

https://hdl.handle.net/1912/3457

As published

https://doi.org/10.1029/2007PA001532

DOI

10.1029/2007PA001532

Keyword

Coral geochemistry; Little Ice Age; Temperature and salinity

Abstract

We use geochemical and isotope measurements on a 225-year old brain coral (Diploria labyrinthiformis) from the south shore of Bermuda (64°W, 32°N) to construct a record of decadal-to-centennial-scale climate variability. The coral was collected alive, and annual density bands visible in X radiographs delineate cold and warm seasons allowing for precise dating. Coral skeletons incorporate strontium (Sr) and calcium (Ca) in relative proportions inversely to the sea surface temperature (SST) in which the skeleton is secreted. Previous studies on this and other coral colonies from this region document the ability to reconstruct mean annual and wintertime SST using Sr/Ca measurements ( Goodkin et al., 2007 , 2005). The coral-based records of SST for the past 2 centuries show abrupt shifts at both decadal and centennial timescales and suggest that SST at the end of the Little Ice Age (between 1840 and 1860) was 1.5° ± 0.4°C colder than today (1990s). Coral-reconstructed SST has a greater magnitude change than does a gridded instrumental SST record from this region. This may result from several physical processes including high rates of mesoscale eddy propagation in this region. Oxygen isotope values (δ 18O) of the coral skeleton reflect changes in both temperature and the δ 18O of seawater (δOw), where δOw is proportional to sea surface salinity (SSS). We show in this study that mean annual and wintertime δ 18O of the carbonate (δOc) are correlated to both SST and SSS, but a robust, quantitative measure of SSS is not found with present calibration data. In combination, however, the Sr/Ca and δOc qualitatively reconstruct lower salinities at the end of the Little Ice Age relative to modern day. Temperature changes agree with other records from the Bermuda region. Radiative and atmospheric forcing may explain some of the SST variability, but the scales of implied changes in SST and SSS indicate large-scale ocean circulation impacts as well.

Description

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): PA3203, doi:10.1029/2007PA001532.

Collections

Marine Chemistry and Geochemistry (MC&G)