Fig. 4

Pictures of etch marks resulting from calcein staining. Etching is indicated by red arrows. The left panel shows etching immediately post-immersion, and the right panel shows etching after six months of growth. Black marks on the shells indicate annuli. Images marked A represent the 125 mg L⁻¹ concentration at a 12-h immersion, images marked B are 125 mg L⁻¹ for 24 h, images marked C are 250 mg L⁻¹ for 12 h, and images marked D are 250 mg L⁻¹ for 24 h.