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| Titel |
Re-evaluating Sr/Ca-derived records of post-industrial era warming from the sclerosponge Ceratoporella nicholsoni |
| VerfasserIn |
Peter Swart, Amanda Waite, Brad Rosenheim, Angela Rosenberg |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250152998
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| Publikation (Nr.) |
 EGU/EGU2017-17918.pdf |
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| Zusammenfassung |
| While the Sr/Ca ratios in the skeletons of sclerosponges appear to be well correlated with
water temperature, the measurement of Sr/Ca ratios from several specimens by different
workers yields unexpectedly large (up to 4.4 ˚ C) increases in temperature over the past 150
years, greater than spatially and temporally averaged observational temperature increases.
One possible explanation for the larger than anticipated temperature changes in these samples
arises from the calibration between temperature and Sr/Ca which was derived from
specimens growing at relatively high temperatures, 26 to 30 ˚ C. In order to improve the
calibration, we acquired a number of samples of sclerosponges collected from localities and
water depths at lower average water temperatures, and combined the Sr/Ca measurements
from bulk samples representing the last ∼15 years of growth with the previous
calibration dataset. Analysis of these samples reveals that the calibration between the
Sr/Ca ratio in sclerosponge skeletons and temperature is better approximated by an
exponential curve with a lower slope at cooler temperatures. This is similar to the
relationship between Mg/Ca and temperature seen in foraminifera. Application of
this equation to published data reduces the increase in temperature reconstructed
from Sr/Ca ratios in the deeper-occurring samples to values in better agreement
with spatially and temporally gridded observational ocean temperature data sets. |
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