Shell of the Great Scallop Pecten maximus as a high-frequency archive of paleoenvironmental changes - art. no. Q08001

2005

Article référencé dans le Web of Science WOS:000231141100001

Chauvaud L., Lorrain A., Dunbar R. B., Paulet Y. M., Thouzeau G., Jean F., Guarini J. M., Mucciarone D.

Geochemistry Geophysics Geosystems, 2005, 6, p. NIL_1-NIL_15 ISSN 1525-2027

We investigate the environmental and biological controls on oxygen isotope ratios in the shells of modern Pecten maximus bivalves collected alive in the Bay of Brest (France). Seasonal delta(18)O profiles, obtained by drilling the daily calcite ridges deposited at the surface of the left valve, were compared with in situ measurements of temperature and salinity. We show that P. maximus delta(18)O values accurately track seasonal variations in bottom water temperature. Shell growth rate has no significant effect on shell delta(18)O values. Our study demonstrates that daily variations in water temperature can be reconstructed within about 0.5 degrees C. Temperatures estimated with the paleotemperature equation established in this study were compared with temperatures derived from previously published equations. The comparison indicates that the most commonly used paleotemperature equation for biogenic calcite (Epstein et al., 1953) provides inaccurate temperature estimates, but the Kim and O'Neil (1997) equation, established from abiogenic calcite precipitation, provides results very similar to ours and should therefore be used for scallop individuals coming from populations where proper empirical calibration cannot be done. Pecten maximus bivalves precipitate calcite in isotopic equilibrium with seawater, produce large daily growth striae, are stenohaline, and are well preserved in archeological and geological deposits, making them an excellent high-frequency archive of paleoenvironmental change.

PAR00000389