The Acropora millepora or milli staghorn coral many reefs that have a high coral cover also have surprisingly turbid conditions, like fringing reefs around the inshore continental islands of the Great Barrier Reef Lagoon and in the Indian Ocean. Acropora millepora is a hard coral. As a broadcasting species, it has been found to reach 5.1 mm in diameter during a period of 9.3 months. This species grows mostly vertically, which leads to a bushy morphology that is semi-erect. Polyps extend from vertical branch tips on an average of 1.2 to 1.5 cm, and these polyps are non-reproductive. Laterally, though, most regions are reproductive Polyps are on average about 1-2 mm in diameter Modules (in this case, polyps) that comprise a colony often show some degree of polymorphism Reef building corals, such as Acropora millepora, can reproduce sexually in an event called "mass spawning". This occurs once a year, around 3 nights in early summer when the moon is nearly full. Mass quantities of eggs and sperm are released simultaneously from the huge numbers of coral colonies, many belonging to different species and genera .

Colony size has no effect on the number of eggs or sperm per polyp, on the testes volume per polyp Like all coral, Acropora millepora are social, sessile animals. As social animals, they form a coral reef. This is mainly made of material which has its origin in live coral, coral rubble, dead standing coral, and coralline rock 86% of the rest is sand They are affected by both predation and competition. As far as predation goes, Acanthaster planci (the crown-of-thorns starfish) is regarded as a specialist corallivore. This starfish is adapted to feed on a variety of different coral forms and types. With its flexible body, it is able to feed on various coral sizes and shapes. It also produces a waxy esterase that is able to break down the main energy reserves of its coral prey Reef building corals, such as Acropora millepora, can reproduce sexually in an event called "mass spawning". This occurs once a year, around 3 nights in early summer when the moon is nearly full. Mass quantities of eggs and sperm are released simultaneously from the huge numbers of coral colonies, many belonging to different species and genera. Colony size has no effect on the number of eggs or sperm per polyp, nor on the testes volume per polyp.

Coral also has the ability to be a suspension feeder. Usually, we think of fine suspended particulate matter in high concentrations to be a stress on nearshore coral reefs. Because coral is able to be a passive suspension feeder, it can actually serve as a food source . Various sources of it include suspended sediment, detrital matter, excretory products from other animals, and coral mucus. These particles are also exposed to colonization by macroalgae and bacteria, which makes this a more organically valuable food source.

The contribution of zooplankton feeding is not all that different from it feeding, in terms of maximum rate of it carbon assimilation. Also, when particle concentration is high, its feeding can cover half of the carbon and one-third of the nitrogen that is necessary for coralline tissue growth. As it concentrations increase, Acropora millepora ingestion rates increase linearly . Successfully capturing and ingesting fine particles only increases 1-fold for every 8-fold increase in food availability.

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Author: Jackie H

Published: 03/2008

Photo Credit: http://www.nwaquatics.com/images/acro_mille_purple.jpg