Galaxea astreata

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Galaxea astreata
Galaxea-astreata-field.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Cnidaria
Class: Hexacorallia
Order: Scleractinia
Family: Euphylliidae
Genus: Galaxea
Species:
G. astreata
Binomial name
Galaxea astreata
(Lamarck, 1816)
Synonyms
List
  • Anthophyllum clavusDana, 1846
  • Anthophyllum musicale(Linnaeus, 1767)
  • Caryophyllia astreataLamarck, 1816
  • Galaxea clavusDana, 1846
  • Galaxea musicalis(Linnaeus, 1767)
  • Galaxea negrensisNemenzo, 1979
  • Galaxea susanaeNemenzo & Ferraris, 1982
  • Madrepora musicaleLinnaeus, 1767

Galaxea astreata is a common and cosmopolitan large polyp scleractinian coral, (stony, hard coral) in the family Euphylliidae . It has a sub-massive morphology. It is found in the Indo-Pacific [2] and is the most abundant coral species in Xuwen Coral Reef National Nature Reserve. G. astreata is acclimatized to water temperatures ranging from about 27 ± 0.5 °C. [3] It is generally a shallow-water coral and is commonly seen at a depth of around 15 meters. It can range from a depth of 1 meter to 30 meters. [4] It generally prefers clear, salt waters over turbid brackish waters. [5]

Contents

Description

Galaxea astreata has a very distinctive skeleton structure, which is made of calcium carbonate (CaCO3). Corallites, the skeletal cup formed by individual polyps, are very plate-like. They are about 3-4.5 in diameter. They are also well spaced. [6] The coral can has a symbiotic relationship with zooxanthellae living inside of the coral. [5] Colonies of G. astreata are either sub-massive, columnar, or encrusting, meaning they can either be irregularly shaped, growing upward like columns, or impinging on a hard substrate. Colonies can grow to be over two meters long. The polyps are usually found to be pink, grey, green, or brown in color. [6]

Feeding

Galaxea astreata eat zooplankton and coral larvae that float by. Corals tend to feed at night since planktivorous fishes are sleeping. G. astreata expands its polyps to feed during the day, and contracts them at night. It is an effective predator, and like other massive growth forms, G. astreata will be an even more efficient when the larvae starts sinking in the water column so that it is easier for the coral to catch. [7]

Reproduction

Galaxea astreata is a broadcast spawner, as gametes are released into the water for external fertilization. After the gamete is fertilized, the planulae, or the larval form of the coral, develops inside the plankton. [5] G. astreata can either be a hermaphrodite, having both male and female gametes, or a gonochore, having gametes of only one sex. [5]

Threats and coral bleaching

The coral coverage rate in Xuwen rapidly decreased due to human activity and other environmental factors causing a decline in the G. astreata. [8] Some detrimental human activities include overuse of fisheries and extraction, eutrophication and siltation, and pollution. [9] Though G. astreata is more resistant to environmental changes than other coral species (i.e. Accropora spp.), [10] it had a 100% mortality rate after the El Niño phenomenon of 1997-1998, starting with slow death of tissue fragments in the first 4 months after the disturbance. [11] However, G. astreata was not the only coral affected, as this 1998 coral bleaching event reduced the richness of all coral species off the coast of Sesoko Island, Japan by 61% and reduced coral cover by 85%. Temperatures rose 2.8 °C above average from this one event alone. [12] Coral bleaching events cause a loss of the symbiotic algae (zooxanthellae) and/or a loss of pigment (color mostly derived from zooxanthellae). It is a global phenomenon that is most likely linked to global climate change and rising ocean temperatures, as well as ocean acidification. [12]

Related Research Articles

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<span class="mw-page-title-main">Scleractinia</span> Order of Hexacorallia which produce a massive stony skeleton

Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a mouth is fringed with tentacles. Although some species are solitary, most are colonial. The founding polyp settles and starts to secrete calcium carbonate to protect its soft body. Solitary corals can be as much as 25 cm (10 in) across but in colonial species the polyps are usually only a few millimetres in diameter. These polyps reproduce asexually by budding, but remain attached to each other, forming a multi-polyp colony of clones with a common skeleton, which may be up to several metres in diameter or height according to species.

<span class="mw-page-title-main">Staghorn coral</span> Species of coral

The Staghorn coral is a branching, stony coral, within the Order Scleractinia. It is characterized by thick, upright branches which can grow in excess of 2 meters in height and resemble the antlers of a stag, hence the name, Staghorn. It grows within various areas of a reef but is most commonly found within shallow fore and back reefs, as well as patch reefs, where water depths rarely exceed 20 meters. Staghorn corals can exhibit very fast growth, adding up to 5 cm in new skeleton for every 1 cm of existing skeleton each year, making them one of the fastest growing fringe coral species in the Western Atlantic. Due to this fast growth, Acropora cervicornis, serve as one of the most important reef building corals, functioning as marine nurseries for juvenile fish, buffer zones for erosion and storms, and center points of biodiversity in the Western Atlantic.

<i>Montipora</i> Genus of corals

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<i>Galaxea fascicularis</i> Species of coral

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<i>Millepora platyphylla</i> Species of hydrozoan

Millepora platyphylla is a species of fire coral, a type of hydrocoral, in the family Milleporidae. It is also known by the common names blade fire coral and plate fire coral. It forms a calcium carbonate skeleton and has toxic, defensive polyps that sting. It obtains nutrients by consuming plankton and via symbiosis with photosynthetic algae. The species is found from the Red Sea and East Africa to northern Australia and French Polynesia. It plays an important role in reef-building in the Indo-Pacific region. Depending on its environment, it can have a variety of different forms and structures.

<i>Diploria</i> Genus of corals

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<i>Euphyllia ancora</i> Species of coral

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Coelastrea aspera is a species of stony coral in the family Merulinidae. It is a colonial species native to the Indo-Pacific region where it occurs in shallow water. It was first described by the American zoologist Addison Emery Verrill in 1866 as Goniastrea aspera but it has since been determined that it should be in a different genus and its scientific name has been changed to Coelastrea aspera. This is a common species throughout much of its wide range and the International Union for Conservation of Nature has rated its conservation status as being of "least concern".

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Miguel Mies is a Brazilian academic, oceanographer, and researcher. He is currently a professor at the Oceanographic Institute of the University of São Paulo (IO-USP) and leads the Coral Reefs and Climate Change Laboratory (LARC). He also serves as the research coordinator for the Coral Vivo Project and is the vice president of the Coral Vivo Institute.

References

  1. Hoeksema, B., Rogers, A. & Quibilan, M. 2008. Galaxea astreata. The IUCN Red List of Threatened Species. Version 2016.1.
  2. Kenkel, Carly D.; Bay, Line K (23 August 2017). "Novel transcriptome resources for three scleractinian coral species from the Indo-Pacific". GigaScience. 6 (9): 1–4. doi:10.1093/gigascience/gix074. PMC   5603760 . PMID   28938722.
  3. Huang, Yuanjia; Yuan, Jigui; Zhang, Yanping; Peng, Hiupai; Liu, Li (June 7, 2018). "Molecular cloning and characterization of calmodulin-like protein CaLP from the Scleractinian coral Galaxea astreata". Cell Stress and Chaperones. 23 (6): 1329–1335. doi:10.1007/s12192-018-0907-0. PMC   6237685 . PMID   30105591.
  4. "IUCN Red List of Threatened Species: Galaxea astreata". IUCN Red List of Threatened Species. 2008-01-01. Retrieved 2020-04-12.
  5. 1 2 3 4 "Coral Trait Database | Galaxea astreata". coraltraits.org. Retrieved 2020-04-10.
  6. 1 2 "WoRMS - World Register of Marine Species - Galaxea astreata (Lamarck, 1816)" . Retrieved March 28, 2020.
  7. Fabricius, Katharina E.; Metzner, Juliane (May 13, 2004). "Scleractinian walls of mouths: Predation on coral larvae by corals". Coral Reefs. 23 (2). doi:10.1007/s00338-004-0386-x. S2CID   35809820.
  8. Shen, C; Liu, CW; Liu, L. "Heat-induced stress genes Hsp70, Hsp90 and chloroplast psaA and psbA gene expressions of Galaxea astreata endosymbiotic zooxanthella revealing the ability of tolerance and recovery". J Trop Oceanogr: 35:72–78.
  9. Stanley, G. (1994). "Eberhard Gischler (ed): Mojsisovics on the Triassic Reefs of the Dolomites (1879)". Coral Reefs. 21 (2): 229–230. doi:10.1007/s00338-002-0225-x. ISSN   0722-4028. S2CID   42611747.
  10. Huang, Yuanjia; Yuan, Jigui; Zhang, Yanping; Peng, Hiupai; Liu, Li (June 7, 2018). "Molecular cloning and characterization of calmodulin-like protein CaLP from the Scleractinian coral Galaxea astreata". Cell Stress and Chaperones. 23 (6): 1329–1335. doi:10.1007/s12192-018-0907-0. PMC   6237685 . PMID   30105591.
  11. Obura, D. O. "Differential bleaching and mortality of eastern African corals." WIOMSA, 2001.
  12. 1 2 Loya, Y.; Sakai, K.; Yamazato, K.; Nakano, Y.; Sambali, H.; Woesik, R. van (2001). "Coral bleaching: the winners and the losers". Ecology Letters. 4 (2): 122–131. doi:10.1046/j.1461-0248.2001.00203.x. ISSN   1461-0248.