Mg/Ca and Sr/Ca ratios of ostracod valves from living species of Lake Geneva

Détails

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Etat: Public
Version: de l'auteur
ID Serval
serval:BIB_4AB727BF0D0A
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Mg/Ca and Sr/Ca ratios of ostracod valves from living species of Lake Geneva
Périodique
Chemical Geology
Auteur(s)
Decrouy L., Vennemann T.W., Ariztegui D.
ISSN
0009-2541
Statut éditorial
Publié
Date de publication
2012
Peer-reviewed
Oui
Volume
314
Pages
45-56
Langue
anglais
Résumé
The Mg/Ca and Sr/Ca ratios of living ostracods belonging to 15 different species and sampled monthly over a one year-cycle at five sites (2, 5, 13, 33, and 70 m water depths) in western Lake Geneva (Switzerland) are compared to the oxygen and carbon isotope compositions measured on the same samples as well as to the temperature and chemical composition of the water (δ18OH2O, δ13CDIC, Mg/CaH2O, and Sr/CaH2O) at the time of ostracod calcification. The results indicate that trace element incorporation varied at the species level, mainly because of the ecological and biological differences between the different species (life-cycle, (micro-)habitat preference, biomineralisation processes) and the control thereof on trace element incorporation of the ostracods. In littoral zones, the Mg/Ca and Sr/Ca of ostracod valves increase as temperature and Mg/Ca and Sr/Ca of water increase during spring and summer, hence reflecting mainly seasonal variations. However, given that for Lake Geneva the Mg/Ca and Sr/Ca of water also vary with temperature, it is not possible to distinguish the effects of temperature from those of changes in chemical composition of water on the trace element content in ostracod valves. Results support that both water temperature and water Mg/Ca and Sr/Ca ratios control the final trace element content of Cyprididae valves. In contrast, the trace element content of species living in deeper zones of the basin is influenced by variations in the chemical composition of the pore water for the infaunal species. Trace element content measured for these specimens cannot, therefore, be used to reconstruct the compositions of the water lake bottom. In addition, incorporation of Mg and Sr into the shell differs from one family, sub-family, or even species to the other. This suggests that the distinctive Mg and Sr partition coefcients for the analysed taxa result from different valve calcification strategies that may be phylogenetic.
Mots-clé
Ostracod, Shell chemistry, Trace element ratios, Mg/Ca, Sr/Ca, Biomineralisation
Création de la notice
14/10/2011 12:37
Dernière modification de la notice
20/08/2019 13:58
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