Acropora

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Acropora
Acropora nasuta

Acropora nasuta

Systematics
Trunk : Cnidarians (Cnidaria)
Class : Flower animals (anthozoa)
Subclass : Hexacorallia
Order : Hard corals (Scleractinia)
Family : Acroporidae
Genre : Acropora
Scientific name
Acropora
Oken , 1815

Acropora is the most species-rich genus of hard corals (Scleractinia).

While there are only three species in the Caribbean and the acropores around Hawaii are missing, the Australian hard coral specialist Veron gives 73 species for eastern Australia alone. The exact number of species in the entire Indo-Pacific is unknown, as there are many forms due to the networked evolution of this genus, the species status of which cannot be determined.

features

The polyps of the acropores are only one to three millimeters long. A large polyp at the end of each branch is characteristic. The terminal polyps also often have a special color and give the mostly brownish coral colony color. The axial polyps at the end of the branches have six tentacles, the radial polyps have twelve tentacles that they stick out at night to catch plankton .

In German, the acropores are often called antler corals or table corals, depending on their growth form. Like most other hard corals, they live in a symbiotic relationship with small algae ( zooxanthellae ), which supply the acropores with nutrients. The acropores are therefore dependent on bright locations.

Acropores dominate the reefs in many places and form real monocultures . They grow very quickly and make up an estimated 25% of the reef formation. In Barbados it has in Acropora cervicornis found an annual increase of 26 centimeters. While the flower animals grow in the shallow water and on the reef roofs mostly in the shape of a bush or antler, they often form table-shaped sticks on the reef slopes and grow horizontally outwards in order to catch as much light as possible.

species

Flight through a stack of CT images of an Acropora coral from three views. It can be seen that the “arms” consist of numerous hollow passages. The coral was glued into a stone with hot glue and then overgrown it.
Flight around the 3D object generated from the above data.
Elk antler coral
( Acropora palmata )
Acropora latistella
Acropora grandis

Subgenus Isopora

Acropora subgenus

threat

" Coral bleaching ": Acropora off the Pacific island of Réunion (January 2006)

Like other hard coral species , Acropora are threatened by the permanent warming and acidification of the oceans caused by human-made global warming through " coral bleaching ".

Aquarium keeping

Acropores can also be grown in well-maintained saltwater aquariums . If the water conditions are good, you can achieve length increases of 16 centimeters per year. They can easily be artificially propagated by fragmenting larger colonies. In the meantime there are many coral breeders who multiply acropores and try to keep shapes as colorful as possible. Today it is no longer necessary to import acropores from coral reefs.

literature

  • Julian jump: corals. Dähne Verlag, 2000, ISBN 3-921684-87-0
  • SA Fosså, AJ Nilsen: Coral reef aquarium. Volume 4, Birgit Schmettkamp Verlag, Bornheim, ISBN 3-928819-05-4
  • Erhardt / Moosleitner: Mergus Sea Water Atlas. Volume 2. Mergus-Verlag, Melle, 1997, ISBN 3-88244-112-7
  • Erhardt / Baensch: Mergus Sea Water Atlas. Volume 4. Mergus-Verlag, Melle, 1998, ISBN 3-88244-023-6
  • Erhardt / Baensch: Mergus Sea Water Atlas. Volume 5. Mergus-Verlag, Melle, 2000, ISBN 3-88244-115-1

Web links

Commons : Acropora  - collection of images, videos and audio files

Individual evidence

  1. ↑ Elizabeth M. Hemond, Stefan T. Kaluziak, Steven V. Vollmer: The genetics of colony form and function in Caribbean Acropora corals . In: BMC Genomics . tape 15 , no. 1 , December 17, 2014, doi : 10.1186 / 1471-2164-15-1133 , PMID 25519925 , PMC 4320547 (free full text).