''Turbinaria stellulata'', also known as disc 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 ...

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 ...

stony coral 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 ...

Dendrophylliidae Dendrophylliidae is a family of stony corals. Most (but not all) members are azooxanthellate and thus have to capture food with their tentacles instead of relying on photosynthesis to produce their food. The World Register of Marine Species incl ...

. It is native to the Indo-Pacific region. 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 rated its conservation status as being " vulnerable".

Description

''Turbinaria stellulata'' tends to be submassive with encrusting margins and does not produce vertical structures to any extent. 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 about in diameter and have thick walls. This coral 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 that houses

symbiont 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 ...

dinoflagellates in its tissues. It is usually some shade of brown or green, but other colours sometimes occur, depending on which species of symbiont is present. Colonies are dome-shaped and grow to a diameter of about .

Distribution and habitat

''Turbinaria stellulata'' occurs in the Indo-Pacific region. Its range extends from the Red Sea and Madagascar to tropical Australia, southern Japan and the South China Sea. It occurs on upper reef slopes at depths from 2 to 15 metres (6 to 50 ft ), and unlike other corals in its genus '' Turbinaria'', it seems to avoid turbid water.

Biology

As a zooxanthellate coral, ''Turbinaria stellulata'' gets part of its nutritional needs from the

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 ...

symbionts in its tissues, but also extends its polyps to feed, mostly at night. Colonies are either male or female and are broadcast spawners. All the colonies in an area liberate their eggs and sperm into the sea in a spawning event which is synchronised with the phases of the moon. The

planula A planula is the free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species and also in some species of Ctenophores. Some groups of Nemerteans also produce larvae that are very similar to the planula, which ...

larvae that develop form part of the

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

and eventually settle in a suitable location on the seabed.

Status

In general, the threats that stony corals face include global

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 ...

with the resulting rise in the temperature of sea water,

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 ...

, increased severity of storms which damage reefs, increased frequency of El Niño events,

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 alg ...

and the increasing incidence of coral diseases. The population trend of ''Turbinaria stellulata'' has not been monitored but as a shallow water coral it is affected by these factors. It has a wide range but is an uncommon species and the

has assessed its conservation status as being " vulnerable".

References

{{Taxonbar, from=Q3954497 Dendrophylliidae Corals described in 1816