Thursday, August 24, 2017

Corals as Colonies – Life-forms

Although some coral genera are solitary, i.e. they form separate individuals (e.g. Cycloseris, p. 24 of the Coral Finder), the majority of scleractinian corals form colonies made up of a number of individuals.  These individuals reproduce asexually by budding (see asexual reproduction article for more information), so that over time the colony becomes larger and is composed of more and more individuals (e.g. Acropora, p. 1 of the Coral Finder).  The colonial nature of corals has wide ranging implications for coral ecology, biology and identification.  One of the main consequences is that colonies may grow into a wide range of shapes or morphologies as new individuals are added and grow.  These shapes are termed life forms or growth forms, and can be used as the first step in identifying corals, as certain genera and species grow into specific life forms.

Life form describes the overall shape of the coral, and is synonymous with growth form or morphology.  It is important to be aware that there are three sources of confusion when discussing a coral’s life form: 1) many different terms exist for similar life forms, 2) a single colony may exhibit more than one life form; in this instance the predominant life form is generally used, 3) these shapes exist on a continuum rather than being clear cut, separate definitions, so a degree of subjectivity is inherent to the topic.



Suggested Reading

  • Veron, J. E. N. (2000). Corals of the World. Melbourne: Australian Institute of Marine Science.