BIVALVE SKELETONS RECORD SEA-SURFACE TEMPERATURE AND DELTA-O-18 VIA MG CA AND O-18/O-16 RATIOS/

Paleotemperatures have been widely deduced from skeletal O-18/O-16 rat ios, but these are also dependent on salinity, Without an independent measure of salinity, O-18/O-16 ratios cannot provide accurate data on past temperature and climate, We grew marine mollusks (bivalves) in th e field while real-time data on local seawater temperature and chemist ry (Mg, Ca, delta(18)O, and salinity) were gathered, Here we show that for Mytilus trossulus, skeletal Mg/Ca ratios provide an accurate meas ure of temperature and that weekly sea-surface temperatures may be est imated with an apparent accuracy of approximately +/- 1.5 degrees C, T hus, with analyses of both Mg/Ca and delta(18)O from the same specimen , it is possible to determine seawater temperature and delta(18)O.