Cyprideis torosa is a species of ostracode that inhabits a wide range of aquatic habitats in which its low Alk/Ca requirement is met. Its fossil remains are widely used in palaeoecological studies of coastal environments and inland salt lakes. We collected C. torosa from 20 water bodies near Valencia, Spain. Temperature, chlorophyll a concentration, electrical conductivity, and the concentration of major ions and oxygen isotopes were measured at each site. Between 2 and 20 live individuals of C. torosa were collected per site, their instar stage and sex determined and their shell chemistry (Mg/Ca, Sr/Ca and carbon and oxygen isotope composition) analyzed. Three of these sites were sampled monthly for one year, and ostracode population structure and shell chemistry (20-40 shells) were analyzed. The water chemistry varied widely between sites. TDS (total dissolved solids) ranged from 0.5 to 71.8 g/L but chloride was always the dominant anion. There is a significant positive relationship between ostracode and water δ18O except at high TDS (>20 g/L) when shell δ18O values are lower than expected. No effect of either temperature or water Mg/Ca is observed on the Mg/Ca in the ostracode calcite in waters with Mg/Ca < 6 (molar ratio). Ostracode shell Sr/Ca is strongly and significantly related to water Sr/Ca. δ13C values in C. torosa shells are ~2& lower than observed δ13CDIC. These results provide new and more accurate quantification tools to reconstruct past hydrochemistry from C. torosa shells.
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We thank the University of Minnesota Aqueous Geochemistry Lab (Rick Knurr, analyst) and the Stable Isotope Lab (Maniko Solheid, manager) for help in the chemical analyses, the Projects VARECOMED and INCAMEDSELAR from the Spanish Ministry of Science and their leaders Mª Rosa Miracle and Eduardo Vicente, for the collaboration and financial support in this study. We are grateful to the staff at “Salinas de Santa Pola”, and especially to Miguel Cuervo for allowing access and providing information about the area. Special thanks to Guy Wansard for suggesting the collaboration between the authors of this study. We thank Carlos Santiesteban, Blas Valero, Pere Anadón, Peter Frenzel, Jonathan Holmes, Finn Viehberg and Steffen Mischke who made suggestions to an earlier version of this work. We benefitted enormously from very detailed and constructive reviews of the manuscript by Jonathan Holmes and the associate editor (Alfonso Mucci). This is publication 12-03 of Limnological Research Center, University of Minnesota.