Vertical Versus Horizontal Growth Strategies of Coral Frameworks (Tulamben, Bali, Indonesia)

Two different coral framework structures located in a shallow subtidal area on the east coast of Bali are described in this study. One structure is a typical coral carpet with a distinct internal succession of coral taxa and growth forms. It starts with a variety of coral species exhibiting massive, tabular, branching, and platy growth forms settling on volcanic boulders and cobbles. The main body of the coral carpet is composed almost monospecifically of Acropora cf. vaughani, which has filled all accommodating spaces up to the low-water sea level. Mostof this carpet died during the bleaching event of 1998 and the resultant dead Acropora framework is now capped by a platy Montipora assemblage. Some of the Acropora branches within the dead carpet, however, are still alive and display active growth. The Montipora cover protects the dead Acropora framework against mechanical and biological destruction. The few still growing Acropora branches may also contribute to the strength of the framework. The second coral framework is made up almost monogenerically of Montipora . One species of Montipora is of a laminar growth form and produces whorl-like colonies. Within this framework, only part of the Montipora colonies are dead; however, these are intensively fragmented. The fragments have been rapidly settled by a platy Montipora species, which has stabilized the fragments. In this case, the fragment shedding of the Montipora offers the opportunity for progradation of the framework on these fragments. Concerning the Acropora carpet, similar examples from the fossil record of the Miocene era of Spain and Austria have been reported.