ABSTRACT

In two representative patch reefs within the Florida Reef Tract the majority of Acropora cervicornis colonies appear to have developed from broken fragments of parent colonies rather than directly from settled larvae. Following breakage, both the parent and the fragment regenerate polyps to cover the broken area and apical polyps to continue growth (the parent appears to recover more quickly). Fragments first attach to the substrate by growing laterally, thereby forming a stabilizing base. They then begin to grow upward.

Two main morphological growth forms result from this process: (1) Forms which result from branches of the colony fusing with other branches of the colony; and (2) Forms which result from the interaction of the branches of the colony with the surrounding substrate and organisms. Branches of A. cervicornis may grow parallel or cross closely without fusing. However, most branches fuse on contact, with polyps covering the contact area.

On the reefs examined, the A. cervicornis colonies were small, relatively scattered, and did not appear to be a major binding agent. However, within the immediate vicinity of the colonies, they actively bind carbonate rubble and other clastic sediment. Thus in reefs where A. cervicornis is more abundant, this coral could be a major factor in fortification and stabilization. Intergrowth and attachment habits of A. cervicornis are compatible with its occurrence and morphology in many horizons of the Key Largo Limestone, generally interpreted to be a Pleistocene equivalent of the present day Florida patch reefs.