Pocillopora damicornis

Pocillopora damicornis, also called cauliflower coral or lace coral, belongs to the stony coral family Pocilloporidae. It lives in tropical and subtropical waters of the Indian and Pacific Oceans.

Description

This coral forms colonies that can grow into clumps up to 30 cm (12 in) tall. Its wart-like growths, known as verrucae, are arranged more irregularly than in other members of its genus.

It is also more branched than the similar species P. verrucosa. The shape of the colony changes depending on where it grows: in calm water, it is more open and branched, while on upper reef areas with stronger water movement, it is more compact. Colors range from greenish, pink, and yellowish-brown to pale brown.

Distribution and habitat

The cauliflower coral is found from East Africa and the Red Sea to Japan, Indonesia, Australia, Hawaii, Easter Island, and the western coast of Central America. It lives at depths down to about 40 m (131 ft), but is most common between 5 and 20 m (16 and 66 ft), where it often forms dense patches. It occurs on reef slopes, in lagoons, among mangroves, and on wharves, but avoids areas with strong water movement. Because of its vast range, it is one of the most abundant corals.

Biology

This coral builds reefs, grows quickly, and competes well. Its polyps extend their tentacles at night to feed on plankton. When colonies break apart, fragments can settle on the seabed and grow into new colonies—a form of asexual reproduction called fragmentation. It also reproduces sexually.

As a simultaneous hermaphrodite, it retains eggs and sperm inside the coral and releases batches of planular larvae around the time of the new moon. These larvae have a lipid-rich yolk and can stay viable for up to 100 days, giving them great dispersal ability. While brooding larvae occurs across most of its range, in Western Australia it both broods larvae and releases gametes through broadcast spawning; in the Eastern Pacific, only broadcast spawning takes place.

Inside its tissues live microscopic symbiotic dinoflagellate algae (zooxanthellae). These algae produce energy-rich molecules through photosynthesis, which the coral can use. The density of these dinoflagellates changes with seasonal shifts in water temperature, light levels, and dissolved nitrate concentration. This process is dynamic, and under extreme environmental conditions, the coral may expel all the algae, causing bleaching.