Biological alteration of beachrock on Grand Cayman Island, British West Indies

Submerged sheets of beachrock at two localities on Grand Cayman Island, British West Indies are actively being eroded and transformed by pelecypods, polychaete annelids, an unidentified annelid(?), sipunculid worms, spionid worms, algae, sponges and fungi(?). Certain elements of the biota, such as the sponges, serve a purely destructive role whereas other elements, such as the polychaete annelids and algae, serve both a constructive and destructive role. The final result of the biological activity is a limestone that bears little resemblance to the original beachrock.