Publication Date:
2022-05-26
Description:
© The Author(s), 2016. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Chemistry 186 (2016): 11-23, doi:10.1016/j.marchem.2016.07.001.
Description:
Here we provide first evidence that the stable oxygen and carbon isotopic composition
(δ18O, δ13C) of the high-magnesium calcite skeleton red coral Corallium rubrum can be used
as a reliable seawater temperature proxy. This is based upon the analyses of living colonies of
C. rubrum from different depths and localities in the Western Mediterranean Sea. The
assessment of the growth rates has been established through the analysis of growth band
patterns. The δ18O and δ13C compositions show large variability with a significant difference
between the branches and the bases of the colonies. In both coral portions, the δ18O and δ13C
values are highly correlated and show well-defined linear trends. Following the “lines
technique” approach developed by Smith et al. (2000) for scleractinian aragonitic deep-water
corals, our data have been combined with published values for the deep-sea gorgonian corals
Isididae and Coralliidae from Kimball et al. (2014) and Hill et al. (2011) resulting in the
following δ18O temperature equation: T (°C) = 38 -5.05 ± 0.24 x (δ18Ointercept) + 14.26 ± 0.43
(R² = 0.962, p value 〈 0.0001)
The error associated with this equation is ± 0.5 °C at the mean temperature of the data
set, ± 0.7 °C for corals living in 2 °C water and ± 1 °C for coral living in warmer water (17
°C).
The highly significant δ18Ointercept vs. temperature relationship combined with the
“lines technique” method can be reliably applied to the calcitic skeleton to obtain calcification
temperature estimates in the past, although this approach requires the knowledge of the past
δ18O and δ13C composition of seawater and it is labor and time intensive.
Description:
We are grateful for the financial support
of the MISTRALS-PaleoMeX and ENVIMED projects.
Description:
2018-07-05
Keywords:
Red coral
;
Mediterranean Sea
;
Growth rings
;
δ18O
;
δ13C
;
Seawater temperature
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
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