Reef bioerosion : agents and processes

Coral reef maintenance depends on the balance between constructive and destructive forces. Constructive forces are mainly calcification and growth of corals and encrusting coralline algae. Destructive forces comprise physical, chemical, and biological erosion. Bioerosion is considered as the main force of reef degradation because physical erosion (storms) is temporary and localized, and chemical erosion is considered as negligible due to the actual ocean chemistry (Scoffin et al. 1980). Reef bioerosion affects sedimentary and skeletal carbonate substrates. It plays an important role in reef sedimentation, diversity maintenance by creating habitats and by providing food resources, and in biogeochemical cycles (recycling of dissolved Ca2+ and C). Thus, bioerosion is an integral part of the coral reef carbonate balance. The concept of bioerosion was introduced by Neumann (1966). It includes biocorrosion, which refers to destruction of carbonates by chemical means, and bioabrasion which refers to mechanical removal of carbonates by organisms (Golubic and Schneider 1979; Schneider and Torunski 1983).