Oxygen and Carbon Isotopic Composition and Shell Microstructure of the Bivalve Laternula elliptica from Antarctica

Abstract

Oxygen and carbon isotopic measurements were obtained from microsamples of an adult Laternula elliptica, an infaunal, aragonitic, Antarctic bivalve. The δ 18 O values of samples from the exterior surface are, on average (∼ 4.5‰), similar to calculated values inferred to represent precipitation in equilibrium with ambient environmental conditions. This indicates that bulk samples as well as many microsamples from the exterior surface would provide reliable isotopic estimates of paleotemperatures and paleosalinities. Nevertheless, both oxygen and carbon isotopic values from discrete shell areas may be influenced by vital effects