Controls on δ18O and δ13C profiles within the aragonite bivalve Arctica islandica

The geochemistry of Arctica islandica shells provides an opportunity to reconstruct intra-annual resolution climate records in temperate latitudes, and the annual banding allows close temporal constraint. Stable isotope analyses of carbon and oxygen from an Arctica islandica live-collected at 6 m depth from Irvine Bay, UK are presented. Seawater temperature ranges reconstructed from shell delta O-18 agree, within error, with instrumental sea surface temperature measurements. The saw-tooth profile of the seasonal delta O-18 signal (compared with the sinusoidal seawater temperature) indicates that shell accretion rate is not constant throughout the year. yodelling the expected delta O-18 profile from water temperature, salinity and shell growth rate suggest that A. islandica at this site has significant variation in the shell extension rate during the year. Material deposited during shell damage shows a positive shift in delta O-18 m strong ontogenetic effect is seen in delta C-13 and damage to the shell is associated with a significant (>0.5 parts per thousand) and sustained shift of delta C-13.