Mesodesma donacium: Potential application to Peruvian

Reconstructing the past ENSO (El Niño Southern Oscillation) interannual variability requires very high resolution sea surface temperature (SST) proxies. In order to compensate for the lack of coral archive in the Eastern Pacific cold tongue, we studied the potentiality of the bivalve species Mesodesma donacium as a SST tracer for the Peruvian coast. Biomineralisation cycles and growth line formation in the shells are shown to be controlled by tides. The sclerochronology based on fortnightly cycles allowed us to compare local SST data with high resolution shell records. As a result of the high correlation between SST and aragonite d18O, we calculated a linear SST–fractionation relationship for the 14–20 8C range: T 8Cð Þ 17:41F1:15ð Þ 3:66F0:16ð ÞT d18Oarag:=PDB d18Owat:=SMO