Antarctic bivalve Limatula hodgsoni as a proxy for ambient oceanographic conditions at McMurdo Sound ...

• Main Author: Stokes, Dale
• Format: Dataset
• Language: unknown
• Published: SEANOE 2020
• Subjects: bivalve; paleontology; stable isotopes; trace elements; Antarc*; Antarctic; McMurdo Sound
• Online Access: https://dx.doi.org/10.17882/74728; http://www.seanoe.org/data/00635/74728/

Bivalves have been used as proxies to reconstruct ancient oceanographic conditions based on the assumption that their shell calcite is precipitated in near isotopic equilibrium with ambient seawater. Few studies, however, have tested the presumption of equilibrium precipitation for specimens from polar environments. Furthermore, reported isotopic values for polar specimens are largely indicative of disequilibrium precipitation, leading to the conclusion that bivalves living in extreme environments may be poor recorders of ambient oceanography. An analysis of shell chemistry of the Antarctic bivalve Limatula hodgsoni is compared to the local oceanographic data at Cape Armitage, McMurdo Sound, to assess the suitability of extreme environment bivalves as environmental proxies. Results reveal that significant kinetic fractionation occurs during primary-layer shell secretion, resulting in whole-shell isotopic compositions that do not reflect equilibrium with ambient seawater. Secondary-layer shell calcite, ...