''Acropora aculeus'' is a species of

acroporid Acroporidae is a family of small polyped stony corals in the phylum Cnidaria. The name is derived from the Greek ''"akron"'' meaning "summit" and refers to the presence of a corallite at the tip of each branch of coral. They are commonly known a ...

coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secre ...

s found throughout the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by ...

, the central

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

, Australia, southeast Asia, Japan and the East China Sea. It is also present in the western

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

. It is an uncommon species and is particularly prone to

coral bleaching Coral bleaching is the process when corals become white due to various stressors, such as changes in temperature, light, or nutrients. Bleaching occurs when coral polyps expel the zooxanthellae (dinoflagellates that are commonly referred to as al ...

, disease, and

crown-of-thorns starfish The crown-of-thorns starfish (frequently abbreviated to COTS), ''Acanthaster planci'', is a large starfish that preys upon hard, or stony, coral polyps (Scleractinia). The crown-of-thorns starfish receives its name from venomous thorn-like spine ...

predation; it is also harvested for use in aquaria, and the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natur ...

has assessed it as being a "

vulnerable species A vulnerable species is a species which has been categorized by the International Union for Conservation of Nature as being threatened with extinction unless the circumstances that are threatening its survival and reproduction improve. Vulne ...

". Habitat loss is a big concern.

Description

''Acropora aculeus'' forms

corymb Corymb is a botanical term for an inflorescence with the flowers growing in such a fashion that the outermost are borne on longer pedicels than the inner, bringing all flowers up to a common level. A corymb has a flattish top with a superficia ...

ose, pillow-like structures, the horizontal branches being slender and spreading while the upright branches are narrow and shorter. The

corallite A corallite is the skeletal cup, formed by an individual stony coral polyp, in which the polyp sits and into which it can retract. The cup is composed of aragonite, a crystalline form of calcium carbonate, and is secreted by the polyp. Corallit ...

s are distinctive, longer than they are wide, smooth and polished. This coral is usually yellowish or grey, but can be bright bluish-green, and the tips of the branches are often yellow, pale blue, green or brown. It is usually yellow on the

Great Barrier Reef The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, ...

and in the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

, but pale brown in western Australia. It is named as ACR ACUL in Coral Codes.

Distribution and habitat

''Acropora aculeus'' is native to the Indo-Pacific region, its range extending from the east coast of Africa and Madagascar to Taiwan, Japan, Indonesia, Australia and some island groups in the eastern Pacific Ocean. It is endemic to the Philippines distributed in

Samoa Samoa, officially the Independent State of Samoa; sm, Sāmoa, and until 1997 known as Western Samoa, is a Polynesian island country consisting of two main islands (Savai'i and Upolu); two smaller, inhabited islands (Manono Island, Manono an ...

, Great Barrier Reef,

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

, South Vietnam, and the

Marshall Islands The Marshall Islands ( mh, Ṃajeḷ), officially the Republic of the Marshall Islands ( mh, Aolepān Aorōkin Ṃajeḷ),'' () is an independent island country and microstate near the Equator in the Pacific Ocean, slightly west of the Internati ...

. It occurs at depths between about or even deeper. It is found on all parts of the reef, particularly the front slope, and also in lagoons. Its form varies with its degree of exposure to wave action, being more massive in exposed locations and more pillow-like in lagoons.

Status

The reefs on which ''Acropora aculeus'' lives are under threat from global warming, increased ocean acidification and reef destruction. It is a generally uncommon species of coral and is particularly susceptible to

bleaching Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to ...

and coral diseases. The

has assessed its conservation status as being "

vulnerable Vulnerable may refer to: General * Vulnerability * Vulnerability (computing) * Vulnerable adult * Vulnerable species Music Albums * ''Vulnerable'' (Marvin Gaye album), 1997 * ''Vulnerable'' (Tricky album), 2003 * ''Vulnerable'' (The Used album) ...

", considering that 37% of the colonies may be lost in the next thirty years (three generation lengths). Others suggest it is endangered, along with 76% of the Acropora corals.

References

{{Taxonbar, from=Q3949232 Acropora Cnidarians of the Pacific Ocean Cnidarians of the Indian Ocean Marine fauna of Asia Marine fauna of Oceania Marine fauna of Southeast Asia Anthozoa of Australia Vulnerable fauna of Asia Vulnerable fauna of Oceania Corals described in 1846 Taxa named by James Dwight Dana