A quantitative assessment of the mechanical strength of the polar pteropod Limacina helicina antarctica shell

Abstract

This work directly measures the mechanical properties of pteropod shells collected from the Southern Ocean on the 2007 midsummer Subantarctic Zone Sensitivity to Environmental Change (SAZ-Sense) voyage. Shells from the common Southern Ocean pteropod Limacina helicina antarctica were subjected to mechanical analyses in combination with detailed morphological studies. Average hardness and modulus of 2.30 ± 0.07 GPa and 45.27 ± 0.91 GPa, respectively were calculated from several hundred nanoindentation measurements taken from multiple positions across twelve shells of the same species collected under identical conditions. Quantitative data such as these are critical to establish a reference point for future comparative studies and to both understand and evaluate the implications of further ocean acidification on the structural integrity of these common polar calcifiers, particularly in light of their role in the Southern Ocean carbon cycle and food web