Coral reefs and crevices create complex underwater structures. When turbulence is generated by these hard structures, it creates eddies that catch the coral larvae. Because coral larvae are poor swimmer, and are not able to suitable settlement sites on their own, depend on the structures that help shape these eddies, otherwise they are basically lost at sea, with no chance to settle and grow up. 

Nowadays, coral reefs around the globe suffer from repeated environmental disturbances, which are only compounded with climate change. According to coral reef experts, maintaining structural complexity of scales on reefs is vitally important in terms of aiding reef recovery. Relevant management actions include limiting factors that reduce complexity, such as destructive fishing practices, and promoting factors that enhance complexity, as algae-eating fish to the area to prevent algae from growing and smothering corals. 

Plerogyra sinuosa

Commonly known as the grape, bladder, pearl or branching bubble coral Plerogyra sinuosa is a species of “bubble coral” that is distributed throughout the Indian and Pacific Oceans, ranging from the Red Sea to the West and Central Pacific Ocean. P. sinuosa’s bubbles will vary in size and will increase/decrease depending on the amount of light available. With them being larger during the day and smaller at night, as it will make room for its tentacles to reach out to capture food.


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Image: RevolverOcelot

“Giant Green Anemone” (Anthopleura xanthogrammica)

Also known as the Green Surf Anemone, Green Anemone, Solitary Anemone, Rough Anemone, and the Giant Tidepool Anemone, Anthopleura xanthogrammica is a species of Actiniid sea anemone that inhabits low to mid intertidal zones in the Pacific Ocean, ranging from Alaska to Southern California and rarely down to Panama. Like other sea anemones A. xanthogrammica sports several nemoatocyst lined tentacles which are used to paralyze and capture prey that wanders too close. Phoyosynthetic algae of the genus Zoochlorella and dinoflagellates of the genus Symbiodinium live in the tissue and gut of A. xanthogrammica, in this symbiotic relationship they will provide nutrients to the anemone via photosynthesis (partly giving the anemone its green coloration) and in turn they get a safe place to reside. 


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Image: Stan Shebs

Montipora aequituberculata

…a species of “Rice Coral” (Montipora spp.) which is native to the Indo-Pacific region.  Its range extends from the Red Sea and Gulf of Aden, through the Indian Ocean to Japan, the East China Sea, Australia and the west and central Pacific.M. aequituberculata is typically seen on the upper parts of reef slopes, where it is often one of the predominant species. Like many other coral species, M. aequituberculata  possesses zooxanthellae from which it obtains most of its nutritional needs. 

Although it is listed as least concern M. aequituberculata (like many other coral species) faces threats due to habitat destruction and rising sea temperatures which can cause coral bleaching. 


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Image: USFWS

Alcia mirabilis

…sometimes known as the Berried Anemone, Alcia mirabilis is a species of Alciid sea anemone which is known to occur in parts of the Atlantic around the Azores, Portugal, and Spain. It is also common in both the Mediterranean and Red Seas. Alcia mirabilis is noted for the behavior it exhibits at night, where it will change shape, expanding its column and tentacles to catch food. This contrasts with its “day form” which is more compact


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Image: SUBnormali Team


Corals of Sydney #6 Carijoa smithii #marineexplorer by John Turnbull
Via Flickr:
The class Anthozoa contains hard and soft corals. All have polyps; hard coral polyps have 6-sided symmetry and soft coral polyps are 8-sided. Also known as octocorals, the latter have feathery tentacles as you can see here. Carijoa is a successful genus around the world, with some species (C. riisei) becoming invasive in the Pacific. Shiprock.


Corynactis annulata

…is a species of Corallimorpharian cnidarian which is sometimes known as a “Strawberry anemone” despite the fact that is a Corallimorpharian and not a true sea anemone. Corynactis annulata occurs around the southern African coast, ranging from Port Nolloth to Mossel Bay, where it inhabits the intertidal zone. C. annulata is a colonial organism which occurs in clusters and sheets on rocky reefs where it feeds on small planktonic organisms. 


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Image(s): Seascapeza

Grooved Brain Coral (Diploria labyrinthiformis)

..a species of Faviid stony coral which occurs in tropical areas in the west Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea. Grooved brain corals typically inhabit offshore reefs at depths ranging from 1 to 30 meters. Like other corals grooved brain corals are suspension feeders and feed mainly on zooplankton an bacteria, which are captured by polyps which extrude mesenterial tentacles. Diploria labyrinthiformis also host zooxanthella which produce nutrients for the coral via photosynthesis. 


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Image: Janderk

Strawberry Anemone (Actinia fragacea)

…a species of Actiniid sea anemone which is found in the northeastern and eastern Atlantic Ocean. Its range extends from Norway, Scotland and Ireland to the Mediterranean Sea and North Africa, including the Azores, the Canary Islands and Cape Verde. Strawberry anemones typically inhabit the intertidal and sublittoral zone at depths less than 10 meters (33 ft). They are generally found attached to rocks and boulders. 


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Image: Nilfanion

Great Star Coral (Montastraea cavernosa)

…a species of colonial brain coral (Faviidae) which occurs in shallow/moderate Caribbean waters. Great star coral colonies can grow quite large with colonies forming massive “boulders” over 5 feet (1.5 m) wide, with individual polyps the size of human thumbs! Like other corals great star corals are carnivorous, with polyps feeding on passing zooplankton. 


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Image: NOAA

“Elephant Ear Coral” (Amplexidiscus fenestrafer)

…a species of Discosomatid coral which is known to occur throughout the waters of the Indo-West Pacific. Elephant ear corals are often seen in shallow waters 5-25 m in reefs, where they will feed on a wide range of marine invertebrates which get dispatched by its stinging nematocysts, like other corals it can also feed via productions by its symbiotic zooxanthellae.


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Image: Line1