Controls on [delta]18O and [delta]13C profiles within the aragonite bivalve Arctica islandica

• Published in: Holocene (Sevenoaks) Vol. 19; no. 4; p. 549
• Main Authors: Foster, LC, Allison, N, Finch, AA, Andersson, C, Ninnemann, US
• Format: Journal Article
• Language: English
• Published: London Sage Publications Ltd 01-06-2009
• Subjects: Climate; Fossils; Geochemistry; Geological time; Isotopes; Mollusks; Paleoecology
• ISSN: 0959-6836; 1477-0911
• DOI: 10.1177/0959683609104028

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 δ18 O agree, within error, with instrumental sea surface temperature measurements. The saw-tooth profile of the seasonal δ 18 O signal (compared with the sinusoidal seawater temperature) indicates that shell accretion rate is not constant throughout the year. Modelling the expected δ18 O 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 δ18 O. A strong ontogenetic effect is seen in δ13 C and damage to the shell is associated with a significant (>0.5[per thousand]) and sustained shift of δ 13 C. [PUBLICATION ABSTRACT]