Shifts in shell mineralogy and metabolism of Concholepas concholepas juveniles along the Chilean coast

Abstract
Along the west coast of South America, from the tropical zone to the Patagonian waters, there is a significant latitudinal gradient in seawater temperature, salinity and carbonate chemistry. These physical–chemical changes in seawater induce morphological and physiological responses in calcifying organisms, which may alter their energy budget and calcification processes. In this study, we study the organism energy maintenance (i.e. metabolic rate) and mineralogical composition of the shell of the juvenile marine snails Concholepas concholepas (Gastropoda: Muricidae), collected from benthic populations located ~2000km apart, varies across geographic regions along the Chilean coast. We found that in juvenile snails, the calcite:aragonite ratio in the pallial shell margin (i.e. newly deposited shell) increase significantly from northern to southern populations and this increase in calcite precipitation in the shell of juveniles snails was associated with a decrease in oxygen consumption rates in these populations. Our result suggests that calcite secretion may be favoured when metabolic rates are lowered, as this carbonate mineral phase might be less energetically costly for the organism to precipitate. This result is discussed in relation to the natural process such as coastal upwelling and freshwater inputs that promote geographic variation in levels of pH and carbonate saturation state in seawater along the Chilean coast.

Citation
Ramajo, L., Rodríguez-Navarro, A. B., Duarte, C. M., Lardies, M. A., & Lagos, N. A. (2015). Shifts in shell mineralogy and metabolism of Concholepas concholepas juveniles along the Chilean coast. Marine and Freshwater Research, 66(12), 1147. doi:10.1071/mf14232

Acknowledgements
We thank G. Gonzalez, S. Urrejola, B. Arias and J. Pantoja for their kind support in the field and L. Prado in laboratory procedures. This study was supported by grants FONDECYT 1090624–2009 (TOA-SPACE), ANILLO ACT 132. N. A. Lagos and M. A. Lardies acknowledge the Millennium Nucleus Project NC 1200286 ‘Center for the study of multiple drivers on marine socio-ecological systems (MUSELS)’ from the Ministerio de Economı´a, Fomento y Turismo. ARN acknowledges financial support through the grant CGL2011-25906 (Ministerio de Ciencia e Innovacio´n,Spain), RNM-179 group (Junta de Andalucı´a, Spain). L. Ramajo was supported by BECAS CHILE fellowship programme from Comisio´n Nacional de Investigacio´n Cientı´fica y Tecnologica de Chile (CONICYT). Critical insights received form Liz Harper and one anonymous reviewer helped us to improve the final version of this study.

Publisher
CSIRO Publishing

Journal
MARINE AND FRESHWATER RESEARCH

DOI
10.1071/MF14232

Additional Links
http://www.publish.csiro.au/?paper=MF14232

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