Allogeneic and xenogeneic interactions in reef-building corals may induce tissue growth without calcification

Abstract

Tissue growth without the deposition of calcium carbonate skeletons was recorded in two Red Sea hermatypic cnidarians during competitive interactions. Tissue contacts between allogeneic colonies of the hydrocoral Millepora dichotoma resulted in unilateral overgrowth. In xenogeneic interactions between the scleractinian coral Cyphastrea chalcidicum and the cirripede barnacle Savignium dentatum, tissues of the coral always overlaid the plates of the barnacle without depositing calcium carbonate as long as the barnacles were alive (up to five yr). Calcium carbonate was deposited by the coral's tissue on the barnacle's plates only following barnacle death. -from Authors