Sr/Ca in shells of laboratory-grown bivalves (Arctica islandica) serves as a proxy for water temperature – implications for (paleo)environmental research?
Brosset, C.; Höche, N.; Witbaard, R.; Nishida, K.; Shirai, K.; Mertz-Kraus, R.; Schöne, B.R. (2023). Sr/Ca in shells of laboratory-grown bivalves (Arctica islandica) serves as a proxy for water temperature – implications for (paleo)environmental research? Front. Mar. Sci. 10: 1279164. https://dx.doi.org/10.3389/fmars.2023.1279164
In: Frontiers in Marine Science. Frontiers Media: Lausanne. e-ISSN 2296-7745, more
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| Author keywords |
bivalve sclerochronology; water temperature proxy; strontium-to-calcium ratio; shell ultrastructure; growth rate |
| Authors | | Top |
- Brosset, C.
- Höche, N.
- Witbaard, R., more
- Nishida, K.
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- Shirai, K.
- Mertz-Kraus, R.
- Schöne, B.R.
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| Abstract |
Seawater temperature is an essential quantity for paleoclimatological and paleoecological studies. A potential archive that can provide century-long, temporally well-constrained and high-resolution temperature proxy data is available in the form of bivalve shells. However, the number of well-accepted and robust temperature proxies contained in shells is limited to stable oxygen isotopes and carbonate clumped isotopes. Many studies have therefore investigated the possibility to reconstruct temperature from element/Ca properties, specifically Sr/Ca ratios in case of aragonitic shells. As demonstrated here, in agreement with thermodynamic expectations and the lattice strain model, shell Sr/Ca of laboratory-grown Arctica islandica specimens is strongly positively coupled to water temperature. If ultrastructure-related bias is mathematically eliminated, up to 75% of the variability in shell Sr/Ca data can be explained by water temperature. However, in field-grown specimens, this relationship is superimposed by other environmental variables that can hardly be quantified and mathematically eliminated. The explained variability of Sr/Ca is reduced to merely 26% and the prediction uncertainty too large for reliable temperature estimates. Most likely, the equable, less biased conditions in the laboratory resulted in the production of a more uniform shell ultrastructure (with larger and more elongated biomineral units) which in turn was associated with less variable Sr/Ca values and a stronger link to water temperature. Without a detailed understanding and quantification of the factors controlling ultrastructural variations in field-grown bivalves, it remains impossible to employ shell Sr/Ca of wild A. islandica specimens for precise temperature estimates, merely a qualitative temperature reconstruction seems feasible. |
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