Essay about Bioerosion and Reef Ecology - 3553 Words

Bioerosion and Reef Ecology The breakdown of calcareous substrates among coral reefs, or bioerosion, is a facet of reef ecology too often forgotten. The process plays a much more important role than it is usually credited with. Bioeroding species, consisting of many different types of organisms that act on the environment in a seemingly endless variety of ways, interact with the ecosystem and with each other as part of the reef growth and degradation cycle. The degradation portion of this cycle, the part that is most often overlooked, is essential for the development of reefs as the diverse and beautiful habitats that we know them as. Bioerosive interactions are very complex, and a general understanding of the process of bioerosion is†¦show more content†¦Bioerosion is among, if not the most important destructive force on the coral reef (Zubia and Peyrot-Clausade 2001). Total reef growth can be imagined as the sum of calcareous material production by organisms (bioconstruction) and the breakdown of tha t material by others (bioerosion). The interactions between bioconstruction and bioerosion are complex, dynamic, and varying (Naylor 2002). One researcher found that internal sponges alone were responsible for up to 23 kg per m^2 per year of skeletal breakdown (Spencer 2002), which is roughly equal to the fast growth of coral thickets. This illustrates that bioerosive sponges obviously play a significant role in reef ecology. What is bioerosion? Defined as the biological breakdown of calcareous reef materials, bioerosion is a â€Å"major structuring force in coral reefs† (Hutchings 2002). Calcareous materials are accumulated by corals, calcareous algae, and other marine organisms. Corals and calcareous algae, the key players in the production of the reef substrate, produce aragonite and calcite, respectively. Aragonite is a softer material than calcite and is more water soluble (Endean 1982). Underneath the growing surface of the coral reef is generally a material formed of pieces of aragonite coral skeleton (and other materials such as mollusk shells) cemented together by the deposition of calcite by growing calcareous algae. Bioerosion is responsible for the