''Astreopora myriophthalma'', sometimes known as porous star coral, 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 hard coral found in shallow water in the tropical Indian and Pacific Oceans. It is a common species with a wide range 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 natu ...

has assessed its conservation status as being of "

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

Description

''A. myriophthalma'' is a colonial species which forms massive hemispherical or boulder-shaped colonies. 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 conical and evenly distributed over the surface; each has a circular, upright or outwardly-pointing opening. The colour of this coral varies but may be plain or mottled and cream, yellow or brownish-blue. It is similar in appearance to '' Astreopora gracilis'' and '' Astreopora listeri''.

Distribution and habitat

''A. myriophthalma'' has a wide distribution in the tropical Indian and Pacific Oceans. Its range extends from East Africa and the Red Sea through Indonesia and northern Australia to Japan, the Philippines and various Pacific island groups. It occupies a variety of reef habitats at depths between , but avoids

turbid Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Fluids can ...

water.

Ecology

Researchers found that where spionid worms had bored into heads of ''Astreopora myriophthalma'', the areas surrounding their colonies had benefited; the researchers suggested that the

faeces Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...

from the worms had provided extra nutrients for the coral's symbiotic

zooxanthellae 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 ''Sy ...

, and their increased

photosynthetic Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in c ...

activity had increased tissue growth in the coral in the immediate vicinity. The bivalve '' Lithophaga simplex'' also bores into the coral, often in dense populations. This may be a

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 ...

relationship with the bivalve benefiting from protection and increased nutrition, and, despite its structure being weakened, the coral benefiting from the

ammonium The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary a ...

excreted by the molluscs.

Status

''Astreopora myriophthalma'' is the most common species of coral in its genus and has a widespread distribution in the tropical and sub-tropical Indian and Pacific Oceans. It is a comparatively resilient species with no species-significant threats. However its population is likely to be declining because of the degradation of coral reefs, with an estimated loss of around 20% in the reefs on which it grows.

Climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

and

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 ...

are also likely to be threats going forward, and be associated with increased bleaching events and greater incidence of

coral disease Coral diseases, comprising the diseases that affect corals, injure the living tissues and often result in the death of part or the whole of the colony. These diseases have been occurring more frequently in the twenty-first century as conditions beco ...

s as well as man-made hazards such as pollution, sedimentation, damage from fisheries and tourism. The

has assessed its conservation status as being of "

References

{{Taxonbar, from=Q3948351 Acroporidae Cnidarians of the Pacific Ocean Cnidarians of the Indian Ocean Fauna of the Red Sea Marine fauna of Oceania Animals described in 1816 Taxa named by Jean-Baptiste Lamarck