''Acropora aspera'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of staghorn

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 sec ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Acroporidae 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 ...

. It is found on reef flats and in lagoons in very shallow water in the western Indo-Pacific Ocean.

Description

''Acropora aspera'' is a scantily branching,

colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 au ...

coral forming low clumps. The individual branches are slender and only taper towards the tips. 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, the little stony cups from which the polyps grow, vary in size and are crowded closely together. The lower lip of each corallite protrudes slightly. ''Acropora aspera'' varies in colour, being pale green, grey or brown, or occasionally pale blue.

Distribution and habitat

''Acropora aspera'' is found in the Indian Ocean and western parts of the Pacific Ocean. It inhabits reef flats and lagoons and grows in water up to deep. Where coral zoning occurs, it is found between the shallow water ''

Acropora pulchra ''Acropora pulchra'' is a species of colonial staghorn coral in the family Acroporidae. It is found on the back fringes of reefs in shallow water in the western Indo-Pacific Ocean. The oldest fossils of this species date back to the Pleistocene. ...

'', which it closely resembles, and the deeper water ''

Acropora millepora ''Acropora millepora'' is a species of branching stony coral native to the western Indo-Pacific where it is found in shallow water from the east coast of Africa to the coasts of Japan and Australia. It was first described in 1834 by Christian Go ...

''.

Biology

''Acropora aspera'' is a

zooxanthella Zooxanthellae is a colloquial term for single-celled dinoflagellates that are able to live in symbiosis with diverse marine invertebrates including demosponges, corals, jellyfish, and nudibranchs. Most known zooxanthellae are in the genus ''Symbi ...

te coral which harbours

symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

dinoflagellate The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...

s in its tissues. The coral relies heavily on the energy produced during photosynthesis by these algae. In a study off the coast of southern India it was found that this coral grew by extension of the branches and by calcification of the skeleton all year round, but that calcification was reduced in June to September, the south-west monsoon season. This was thought to be due to the greater cloud cover and larger amount of suspended sediment during that season resulting in reduced levels of photosynthesis.

Status

The

IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...

lists ''Acropora aspera'' as being " Vulnerable". This is because, although it has a wide range, it is generally uncommon and populations are believed to be declining. It is particularly prone 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 ...

, a process in which high sea temperatures or stress cause the coral to expel its zooxanthellae and turn white. Other threats it faces are general destruction of coral reefs,

ocean acidification Ocean acidification is the reduction in the pH value of the Earth’s ocean. Between 1751 and 2021, the average pH value of the ocean surface has decreased from approximately 8.25 to 8.14. The root cause of ocean acidification is carbon dioxid ...

, high sea temperatures and coral diseases. The

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 ...

feeds preferentially on ''Acropora'' species corals. This starfish sometimes has sudden increases in population size which may threaten this coral locally.

References

{{Taxonbar, from=Q3952828 Acropora Animals described in 1845 Vulnerable animals