The Caulastrea is a large polyp stony. A polyp grows at each side of the “tube”.
It spreads by scissiparity: first the mouth splits in two, then, the all polyp does until the two polyps are independent from one another. This coral can be found in lagoons and sheltered areas of coral reefs. Colonies of Caulastrea can form coral clusters of 5m in diameter.
The trumpet coral feeds on plankton captured by night thanks to its tentacles with stinging cells. These tentacles are retracted during the day. However, the main nutrient intakes is provided by single-celled algae called zooxanthellae contained in its own tissue. This coral maintains a close symbiosis with them. Under the action of the light and thanks to the carbon dioxide released by the coral, algae grow on the polyp surface and bring it determining nutrients in the skeleton elaboration.
The polyps of that particular species are fluorescents when lighted-up with a UV light.
Fluorescence allows a certain kind of corals to settle in areas with less light. They are able to turn the blue radiation of the sunlight in radiation that can be used by the symbiotic algae contained in its own tissue. Then these algae enjoy a light that develops photosynthesis.
