Fig. 5

The texture and crystal co-orientation strength of A. lessonii shell calcite. (A): Water contaminated with Cd²⁺; (B): water contaminated with Pb²⁺. In (A) measurements 7 and 8 are taken on poisoned shell sections, in (B) measurements 8 and 9 are taken on poisoned shell sections. As the pole figures show, we find for all measurements an axial texture for shell calcite. For all EBSD scans calcite c-axis is perpendicular to outer shell surface and rotates with the curvature of the shell. There is no difference in type of texture or calcite c-axis orientation between chambers secreted in a natural environment and chambers secreted in polluted water. Crystal co-orientation strength is increased, see MUD values in (A), (B). There is a slight increase in crystal co-orientation strength between for the species shown in (B).