ABSTRACT
Cadmium is rapidly bound in sediments of coastal estuaries, but little is known of the effect of this metal on infaunal organisms. In North Inlet, South Carolina (USA), Microphiopholis gracillima, a burrowing brittlestar, exhibits a high incidence of sublethal tissue loss and a rapid regeneration rate. An SEM study was conducted to assess sublethal effects of cadmium on the ultrastructure of regenerating arm ossicles. Arm tip ossicles in all cadmium treatments were asymmetrical with decreased fossae formation. Mid-arm ossicles continued to express decreased fossae development relative to the controls; however, there did not seem to be any morphological changes in developing ossicles near the base of the regenerating arm. The results indicate that the rapid uptake of cadmium along with calcium in the early stages of regeneration seems to interfere with ossicle formation in this species. However, the nature of this interaction and the level at which it interacts with calcification is unclear.
