Equilibrated clumped isotope signatures of land-snail shells observed from laboratory culturing experiments and its environmental implications

Abstract

This study reports on the clumped isotope values (Δ47) of land-snail shells precipitated at known temperatures ranging from 20 °C to 30 °C. Our observed shell Δ47 values fall into the uncertainties of published Δ47–T calibration line (e.g. Kelson et al., 2017), indicating the shell aragonite of land snails is precipitated at clumped isotopic equilibrium without an obvious Δ47 vital effect. The Δ47 data are neither related to the various bulk isotopic input sources (both for δ13C and δ18O) which result from differences in the supplied food and water; nor are they related to the ingested carbonate composition or snail growth rate. Furthermore, we preliminarily applied the Δ47–T calibration (Kelson et al., 2017) to calculate the mean growth temperatures of the parent snails. Results suggest that the clumped isotope values for land-snail shells can be regarded as a useful tool to reconstruct the mean seasonal temperature of snail activity when the environmental parameters are optimum. Future studies should focus on the applicability of this relationship to snails in natural environments where the self-preservation or acclimatization mechanisms are more complex.