Authors:	Brosset, Cornélia Höche, Nils Shirai, Kotaro Mertz-Kraus, Regina Schöne, Bernd R.
Title:	Strong coupling between biomineral morphology and Sr/Ca of Arctica islandica (Bivalvia) : implications for Shell Sr/Ca-based temperature estimates
Online publication date:	20-Apr-2022
Year of first publication:	2022
Language:	english
Abstract:	Bivalve shells serve as powerful high-resolution paleoclimate archives. However, the number of reliable temperature proxies is limited. It has remained particularly difficult to extract temperature signals from shell Sr/Ca, although Sr is routinely employed in other biogenic aragonites. In bivalves, Sr/Ca is linked to the prevailing microstructure and is sometimes affected by kinetics. Here, the hypothesis is tested that temperature can be reconstructed from shell Sr/Ca once microstructure and/or growth-rate-related bias has been mathematically eliminated. Therefore, the relationship between Sr/Ca and increment width, as well as biomineral unit size, has been studied in three different shell portions of field-grown Arctica islandica specimens. Subsequently, microstructure and/or growth-rate-related variation was removed from Sr/Ca data and residuals compared to temperature. As demonstrated, the hypothesis could not be verified. Even after detrending, Sr/Ca remained positively correlated to water temperature, which contradicts thermodynamic expectations and findings from inorganic aragonite. Any temperature signal potentially recorded by shell Sr/Ca is overprinted by other environmental forcings. Unless these variables are identified, it will remain impossible to infer temperature from Sr/Ca. Given the coupling with the biomineral unit size, a detailed characterization of the microstructure should remain an integral part of subsequent attempts to reconstruct temperature from Sr/Ca.
DDC:	550 Geowissenschaften 550 Earth sciences 560 Paläontologie 560 Paleontology
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 09 Chemie, Pharmazie u. Geowissensch.
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-6893
Version:	Published version
Publication type:	Zeitschriftenaufsatz
Document type specification:	Scientific article
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	Minerals 12 5
Pages or article number:	500
Publisher:	MPDI
Publisher place:	Basel
Issue date:	2022
ISSN:	2075-163X
Publisher DOI:	10.3390/min12050500
Appears in collections:	DFG-491381577-G