Fine Structural Features of Destruction of Calcareous Substrata by the Burrowing Sponge Cliona celata

The fine structure of destructive alterations produced by the marine burrowing sponge Cliona celata Grant (1826) as it penetrates calcium carbonate substrata were examined by light and scanning electron microscopy. Typical patterns of destruction included crevice-like etchings and undercuts. Chips of calcium carbonate, etched out of substrata by sponge cells, exhibited microterracing along their surfaces. An identical pattern of relief was seen on walls of pits, formed by the removal of chips. Fine structural features of etchings and the microtopography of pits and chips were similar for Iceland spar (calcite) and molluscan shell.