Order Scleractinia |
The order Scleractinia contains two groups - the colonial species which are largely responsible for coral reef formation and which contain symbiotic photosynthetic zooxanthellae and the solitary corals. This requirement for light by their symbiotic partners lmits the depth to which colonial species can grow. The other group, the solitary corals, may grow on coral reefs but as they lack photosynthetic symbionts have no limits on the depths at which they can thrive. As a result they are found in all of the world's oceans - even around Antarctica.
Like all other cnidarians the polyps are equipped with stinging cells. The solitary corals rely on these for food capture while the reef-forming corals utilize them to varying degrees.
It used to be considered that stony corals only reproduced asexually. We now know that most stony corals on coral reefs reproduce sexually as well. They indulge in a mass spawning - many species of coral release eggs and sperm into the water at the same time. This "big bang" strategy overwhelms the local predators who gorge on this bounty until they can eat no more. The surviving fertilized eggs rapidly develop into planula larvae which settle out onto the bottom and transform into polyps. Almost immediately they start to secrete a limestone skeleton and asexually produce more polyps. Most colonies are relatively slow growing and some corals may be several hundred years old. Reef-forming corals are very sensitive to changes in water temperature and to silt in the water. As a result, human activity on land often leads to stress or death of coral colonies. As the oceans continue to warm up thanks to human production of greenhouse gases some corals undergo the phenomenon of "coral bleaching" in which they kick out their symbiotic algae. It is the algae that provide the color and so the white skeleton becomes clearly visible through the now transparent polyp. Should the temperatures remain elevated the polyps jump ship and leave the skeleton (polyp bailout). When this happens the coral dies. If temperatures drop quickly enough the coral may survive and eventually take new zooxanthellae on board.
I am not a coral expert. These identifications are tentative ...
Enjoy the photos. The future of coral reefs is bleak.
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Acropora cerealis |
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CNID 1627 Acropora cerealis Raja Ampat West Papua |
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CNID 3256 Acropora formosa, Kadavu, Fiji
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Acropora hyacinthus |
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CNID 7077 Acropora hyacinthus? Kadavu, Fiji
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Acropora robusta |
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CNID 7064 Acropora robusta large colony, Kadavu, Fiji
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Acropora species |
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CNID 3493 Acropora species Matamanoa, Fij.
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Acropora species 2 |
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CNID 3255 Acropora species 2, Kadavu, Fiji.
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Acropora species 3 |
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CNID 3493 Acropora species 3, Matamanoa, Fiji.
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Acropora species 4 |

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CNID 3434 Acropora species 4 Matamanoa, Fiji.
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CNID 0015 Coral scene, Matamanoa, Fiji. Various Acropora coral.
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Acropora species 5 |
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CNID 3444 Acropora species 5, Matamanoa, Fiji.
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Acropora tenuis |
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CNID 0009 Acropora tenuis, Matamanoa, Fiji
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Agaricia agaricites Lettuce coral |
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CNID 3440 Agaricia agaricites (maybe), Glover's Reef, Belize.
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Ceratotrochus species |
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CNID 5920 Ceratotrochus species, Solitary coral, Sea of Cortez.
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Ctenactis albitentaculata Mushroom coral |
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CNID 3825 Ctenactis albitentaculata (Order Fungiidae), Kadavu, Fiji.
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CNID 0017 Ctenactis albitentaculata tentacle detail (Order Fungiidae), Kadavu, Fiji.
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Diploria labyrinthiformis Brain coral |
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CNID 0010 Diploria labyrinthiformis Brain coral detail Belize.
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Euphyllia ancora |
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CNID 8496 Euphyllia ancora Kri Eco, Raja Ampat.
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Euphyllia glabrescens |
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CNID 8506 Euphyllia glabrescens Kri Eco, Raja Ampat.
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Favites species |
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CNID 2678 Favites species Raja Ampat West Papua.
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Galaxea species |
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CNID 4412 Galaxea coral colony Taveuni, Fiji.
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Halomitra species |
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CNID 4852 Halomitra species, Taveuni, Fiji.
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Isophyllia sinuosa |
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CNID 3251 Isophyllia sinuosa (Mussidae) Glover's Reef, Belize.
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Madracis decactis |
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CNID 3193 Madracis decactis Hard coral, Glover's Reef, Belize.
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Madracis senaria |
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CNID 3220 Madracis senaria (Astrocoeniidae) Glover's Reef, Belize.
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Mussa angulosa Giant polyp coral |
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CNID 0011 Mussa angulosa Giant polyp coral Belize.
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Plerogyra sinuosa Bubble coral |
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CNID 0012 Plerogyra sinuosa Bubble coral, Raja Ampat.
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Pocillopora species |
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CNID 3605 Pocillopora species (Pocilloporidae) Kadavu, Fiji
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Pocillopora species 2 |
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CNID 3233 Pocillopora coral species 2 Kadavu, Fiji.
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Pocillopora species 3 |
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CNID 7082 Pocillopora species 3, Kadavu, Fiji
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Scolymia cubensis Artichoke solitary coral |
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CNID 3342 Scolymia cubensis, Artichoke solitary coral Glover's Reef, Belize
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Seriatopora species |
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CNID 4504 Seriatopora species Taveuni, Fiji.
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Symphyllia species |
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CNID 2616 Symphyllia species, Raja Ampat, West Papua.
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Tubastraea faulkineri? |
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CNID 0556 Tubastraea cf faulkineri, Kri, Raja Ampat, West Papua.
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Tubastrea micrantha |
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CNID 0014 Tubastrea micrantha
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Tubastraea species |
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CNID 0013 Tubastraea species, Kri Eco, Raja Ampat.
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CNID 1891 Tubastraea species, Raja Ampat, West Papua .
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Turbinaria frondens Yellow cup coral |
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CNID 3263 Turbinaria frondens Yellow cup coral, Kadavu, Fiji.
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CNID 3270 Turbinaria frondens Yellow cup coral, Kadavu, Fiji.
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CNID 3266 Turbinaria frondens Yellow cup coral, Kadavu, Fiji.
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CNID 3279 Turbinaria frondens Yellow cup coral, Kadavu, Fiji.
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