Pavona duerdeni

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Pavona duerdeni
Pavona duerdeni.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Petalonamae
Class: Hexacorallia
Order: Scleractinia
Family: Agariciidae
Genus: Pavona
Species:
P. duerdeni
Binomial name
Pavona duerdeni
Sheppard, C.R.C., 1987

Pavona duerdeni, the porkchop coral, is a coral that forms clusters of cream-colored lobes or discs. [1] They grow in large colonies, divided into ridges or hillocks. The coral is considered to be uncommon due to its low confirmed abundance, yet they are more commonly found in Hawaii, the Indo-Pacific, and  the Tropical Eastern Pacific. They make up some of the largest colonies of corals, and have a slow growth rate, as indicated by their dense skeletons. Their smooth appearance is due to their small corallites growing on their surface. [2]

Contents

Characteristics

Appearance

Pavona duerdeni is usually a uniform grey color, having yellow and brown coloration on the surface of the coral. The coral receives its coloration from the aggregation of the yellow-brown symbiotic zooxanthellae on its hard, lobe-shaped structure. [3] The dimensions of the typical Pavona duerdeni were recorded to be above 1.5m in height and 3m in diameter. Pavona duerdeni are Hermatypic corals, as part of the order Scleractinia, they sediment hard, calcareous material to form the skeleton of the coral upon which the reef is built. Small corallites made out of calcium carbonate skeletons, serving as polyp’s  protection against predation, are found on the surface of Pavona duerdeni, giving the stony coral an overall smooth appearance. [1] The coral’s polyps are only expanded during the day, except when encountered with rapid currents, or water flow, in which case the polyps retreat inside of their corallites. [4]

Pavona duerdeni colonies are considered to be massive corals; with the larger structure divided into small hillocks with irregular ridges. Massive corals are typically boulder-shaped and grow at a slower rate in comparison to corals of reduced size. Due to their stable structures and profiles, massive corals are rarely impacted or disabled by strong wave action, unless the force of impact causes a dislodge from their holdfasts. [5]

Identification of species

The corallites have strongly alternating septo-costae, giving the coral a flower-like pattern seen on the surface of their structure. Pavona duerdeni, coralito.jpg
The corallites have strongly alternating septo-costae, giving the coral a flower-like pattern seen on the surface of their structure.

The species Pavona duerdeni belong the Anthozoans, characterized by being marine invertebrates. In the case of Pavona duerdeni, when  developed, they are  attached to the seabed, while their larvae are dispersed as part of the plankton. Being part of the order Scleractinia, Pavona duerdeni are stony or hard corals, and colonial where the founding polyp settles and starts to secrete calcium carbonate to protect its body. As part of the family Agariciidae, Pavona duerdeni is a reef-building stony coral, with mutualistic symbiotic zooxanthellae, helping achieve nutritional requirements in their tissue. As a members of the genus Pavona, they possess a flower-like pattern seen on the surface of their structure. This occurs due to the corallites on the coral lacking walls between them, while having the corallite connected to their neighbors through septo-costae with clear delineations.

Shown are Pavona duerdeni's polyps. Pavona duerdeni, corallum.jpg
Shown are Pavona duerdeni's polyps.
Pavona duerdeni colonies are considered to be massive corals, typically boulder-shaped; with the larger structure divided into small hillocks with irregular ridges. Pavona duerdeni, in situ.jpg
Pavona duerdeni colonies are considered to be massive corals, typically boulder-shaped; with the larger structure divided into small hillocks with irregular ridges.
Pigmentation of the surface of the coral is attributed to the presence and aggregation of the mutualistic symbiotic zooxanthellae dinoflagellate. Pavona duerdeni, Layang-Layang.jpg
Pigmentation of the surface of the coral is attributed to the presence and aggregation of the mutualistic symbiotic zooxanthellae dinoflagellate.

Fossil record obtained from the Hawaiian archipelago, date Pavona duerdeni as Pleistocene corals, belonging to the first epoch of the Quaternary period, between the Pliocene and Holocene epochs. [6] The first taxonomic reference on record for this species was made in 1980, where the species was considered to be Pavona minuta, referenced as such by other marine scientists until after a closer investigation into the species in 2000 by the Australian Institute of Marine Science, led it to be identified as Pavona duerdeni instead. [7] Pavona duerdeni has similar  corallites like those seen on Pavona clavus, yet they are smaller in size and with more exert primary septo-costae. They have also been compared to, and often confused with Pavona minuta, where corallites are similar to those of Pavona duerdeni, but they are smaller, with less septo-costae and the color ranging from dark green to brown.[ citation needed ]

Distribution and habitat

Geographic distribution

The coral is considered to be uncommon due to its low confirmed abundance, yet has been found in Hawaii, the Indo-Pacific, and the Tropical Eastern Pacific. Large aggregations of Pavona duerdeni have been confirmed in: the Gulf of Panama; the Carrizales, Colima coral reef, located  the Western Mexican coast; [8] in Thailand in Koh Tao reef; [9] in the Johnston Atoll reef; in the Hawaiian Archipelago and the Emperor seamount chain. [6]

Habitat

The habitat for Pavona duerdeni consists of shallow reef environments, forming large colonies on horizontal shallow substrates. Their distribution on the ocean floor has been identified to start at the depth of five meters and below, becoming more abundant at between nine and ten meters of depth, along with the sedimentation of similar massive corals. [8] Pavona duerdeni are identified as reef-building corals, geographically restricted to shallow marine environments. These corals live free or attached to the reef frameworks or rocky substrates, in rubble zones,  as well as soft bottom areas. Ideal temperatures for the coral to thrive have been recorded in the ranges between 25 °C and 29 °C, with an observed threshold of minimum average temperature of 18 °C. [6]

Pavona duerdeni provides the structure necessary for the establishment of coral holobiont, where the coral polyps, and microorganisms including bacteria, archaea, fungi, viruses, and protists, form an ecological unit allowing nitrogen fixation and decomposition of organic materials to occur within the system. [9]

Ecology

Mutualism

Coral polyps, animals, and zooxanthellae, being single-celled organisms, have a mutualistic relationship, where each organism benefit from each other. Through this relationship, Pavona duerdeni get their photosynthetically fixed carbon needed to achieve their needed respiratory requirements. [3] The algal symbiosis with the dinoflagellates leads to photosynthetic production by these symbioses, largely responsible for the life and growth of tropical reef communities. When corals are presented with diverse stress-inducing situations, polyps expel the algal cells and they take on a white appearance, causing “coral bleaching”. When the coral reaches the “bleached” stage,  they have lost all their zooxanthellae cells.[ citation needed ]

Reproduction

As part of the Anthozoa class, Pavona duerdeni, releases spawning-eggs and sperm into the water columns simultaneously. After fertilization, it develops into a planula larvae, with a solid, flattened body using cilia to prevail as free-swimming larvae, further transported by the aid of surface currents. Once the larvae are fully developed, they will settle on the seabed and attach to the substrate, eventually growing into coral polyps. The corals, being hermatypic, will build reefs by depositing hard, calcareous material to form large structures. [8] With time the coral will reach the status of massive coral, creating boulder-sized formations, for the support of life around and within them.[ citation needed ]

Threats

White Plague Disease, is a virus first observed in the 1970’s killing coral tissue, thus responsible for major reef declines worldwide. [9] Corals affected by the plague experience a rapid loss of tissue, leaving with an identifiable line of white in the middle. The white line typically found in the middle of the coral divides the colored, algal-colonized, living sections. Pavona duerdeni have experienced grave loss due to the plague off the coast of Thailand, along with other Pavona species.[ citation needed ]

Contributing to habit loss for reef-associated organisms Pavona duerdeni is affected by diverse challenges reefs face today. Seawater temperature changing as a result of climate change cause stress on the coral. When temperatures are too high, the relationship between corals and their symbiotic microalgae breaks down. This leads to “coral bleaching”, where when the increase in water temperature is significant, then the corals expel the zooxanthellae living in their tissues, causing then the coral to turn completely white, thus “bleaching”. [9] Ocean acidification also has adverse effects on the ocean, for when seawater absorbs some of the excess CO2 from the atmosphere, then this causes the ocean to become more acidic. These acidic conditions dissolve coral skeletons, which make up the structure of the reef, and make it more difficult for corals to grow and reproduce, threatening their existence.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Coral</span> Marine invertebrates of the class Anthozoa

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 secrete calcium carbonate to form a hard skeleton.

<span class="mw-page-title-main">Anthozoa</span> Class of cnidarians without a medusa stage

Anthozoa is a class of marine invertebrates which includes the sea anemones, stony corals and soft corals. Adult anthozoans are almost all attached to the seabed, while their larvae can disperse as part of the plankton. The basic unit of the adult is the polyp; this consists of a cylindrical column topped by a disc with a central mouth surrounded by tentacles. Sea anemones are mostly solitary, but the majority of corals are colonial, being formed by the budding of new polyps from an original, founding individual. Colonies are strengthened by calcium carbonate and other materials and take various massive, plate-like, bushy or leafy forms.

<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">Pillar coral</span> Species of coral

Pillar coral is a hard coral found in the western Atlantic Ocean and the Caribbean Sea. It is the only species in the monotypic genus Dendrogyra. It is a digitate coral -that is, it resembles fingers or a cluster of cigars, growing up from the sea floor without any secondary branching. It is large and can grow on both flat and sloping surfaces at depths down to 20 m (65 ft). It is one of the few types of hard coral in which the polyps can commonly be seen feeding during the day.

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

Galaxea fascicularis is a species of colonial stony coral in the family Euphylliidae, commonly known as octopus coral, fluorescence grass coral, galaxy coral among various vernacular names.

<i>Porites lobata</i> Species of coral

Porites lobata, known by the common name lobe coral, is a species of stony coral in the family Poritidae. It is found growing on coral reefs in tropical parts of the Indian and Pacific Oceans.

<i>Pseudodiploria clivosa</i> Species of coral

Pseudodiploria clivosa, the knobby brain coral, is a colonial species of stony coral in the family Mussidae. It occurs in shallow water in the West Atlantic Ocean and Caribbean Sea.

<i>Dichocoenia</i> Genus of corals

Dichocoenia is a monotypic genus of stony coral in the family Meandrinidae. It is represented by a single species, Dichocoenia stokesii, which is commonly known as pineapple coral, elliptical star coral, or pancake star coral. It is found in the Caribbean Sea and the western Atlantic Ocean. Dichocoenia stokesii has irregular calyces and its form can be either a massive, hemispherical hump or a flat, platform-like structure.

<i>Pavona</i> (coral) Genus of corals

Pavona is a genus of colonial stony corals in the family Agariciidae. These corals are found in shallow waters in the Indo-Pacific region.

<i>Mussa angulosa</i> Species of coral

Mussa is a genus of stony coral in the family Faviidae. It is monotypic, being represented by the single species Mussa angulosa, commonly known as the spiny or large flower coral. It is found on reefs in shallow waters in the Caribbean Sea, the Bahamas and the Gulf of Mexico.

<i>Isopora palifera</i> Species of coral

Isopora palifera is a species of stony coral in the family Acroporidae. It is a reef building coral living in shallow water and adopts different forms depending on the water conditions where it is situated. It is found in the Western Indo-Pacific Ocean as far east as Australia.

<i>Pavona cactus</i> Species of coral

Pavona cactus, the cactus coral, potato chip coral or leaf coral, is a species of colonial stony coral in the family Agariciidae. This coral is found in shallow waters on reefs and in lagoons in tropical parts of the Indo-Pacific region.

<i>Pocillopora verrucosa</i> Species of coral

Pocillopora verrucosa, commonly known as cauliflower coral, rasp coral, or knob-horned coral, is a species of stony coral in the family Pocilloporidae. It is native to tropical and subtropical parts of the Indian and Pacific Oceans.

<i>Dipsastraea speciosa</i> Species of coral

Dipsastraea speciosa is a species of colonial stony coral in the family Merulinidae. It is found in tropical waters of the Indian and Pacific oceans.

<i>Astrangia poculata</i> Species of coral

Astrangia poculata, the northern star coral or northern cup coral, is a species of non-reefbuilding stony coral in the family Rhizangiidae. It is native to shallow water in the western Atlantic Ocean and the Caribbean Sea. It is also found on the western coast of Africa. The International Union for Conservation of Nature lists this coral as being of "least concern". Astrangia poculata is an emerging model organism for corals because it harbors a facultative photosymbiosis, is a calcifying coral, and has a large geographic range. Research on this emerging model system is showcased annually by the Astrangia Research Working Group, collaboratively hosted by Roger Williams University, Boston University, and Southern Connecticut State University

<i>Turbinaria</i> (coral) Genus of corals

Turbinaria is a genus of colonial stony corals in the family Dendrophylliidae. Common names for this genus include disc coral, scroll coral, cup coral, vase coral, pagoda coral and ruffled ridge coral. These corals are native to the Red Sea, Indian Ocean, Japan and the south Central Pacific Ocean.

<i>Schizocyathus</i> Genus of corals

Schizocyathus is a monotypic genus of stony corals in the family Schizocyathidae, the only species being Schizocyathus fissilis. It is a deep water, azooxanthellate coral.

<span class="mw-page-title-main">Euphylliidae</span> Family of marine coral known as Euphylliidae

Euphylliidae are known as a family of polyped stony corals under the order Scleractinia.

<i>Manicina areolata</i> Species of coral

Manicina areolata, commonly known as rose coral, is a colonial species of stony coral. It occurs in shallow water in the West Atlantic Ocean and Caribbean Sea, sometimes as small solid heads and sometimes as unattached cone-shaped forms.

<i>Oxypora glabra</i> Species of coral

Oxypora glabra is a species of large polyp stony coral in the family Lobophylliidae. It is a colonial coral with thin encrusting laminae. It is native to the central Indo-Pacific.

References

  1. 1 2 Fenner, Douglas. 2005. Corals of Hawaii: A field guide to the hard, black, and soft corals of Hawaii and the Northwest Hawaiian Islands, including Midway.
  2. ↑ "Pavona duerdeni". Australian Institute of Marine Science. Retrieved 2013-05-14.
  3. 1 2 ROWAN, R.; POWERS, D. A. (1991-03-15). "A Molecular Genetic Classification of Zooxanthellae and the Evolution of Animal-Algal Symbioses". Science. 251 (4999): 1348–1351. Bibcode:1991Sci...251.1348R. doi:10.1126/science.251.4999.1348. ISSN   0036-8075. PMID   17816191. S2CID   33459727.
  4. ↑ Maté, J. (March 2003). "Ecological, genetic, and morphological differences among three Pavona (Cnidaria: Anthozoa) species from the Pacific coast of Panama". Marine Biology. 142 (3): 427–440. doi:10.1007/s00227-002-0956-9. ISSN   0025-3162. S2CID   80915984.
  5. ↑ "NOAA National Ocean Service Education: Massive corals". oceanservice.noaa.gov. Retrieved 2019-04-07.
  6. 1 2 3 Grigg, R. W. (1997-12-01). "Paleoceanography of coral reefs in the Hawaiian-Emperor Chain revisited". Coral Reefs. 16: S33–S38. doi:10.1007/s003380050239. ISSN   0722-4028. S2CID   9986067.
  7. ↑ Veron, J. E. N.; Pichon, Michel. (1980). Scleractinia of eastern Australia. Part 3. Families Agariciidae, Siderastreidae, Fungiidae, Oculinidae, Merulinidae, Mussidae, Pectiniidae, Caryophylliidae, Dendrophylliidae /. Canberra: Australian National University Press for the Australian Institute of Marine Science. doi:10.5962/bhl.title.60646.
  8. 1 2 3 Reyes Bonilla, Héctor; Escobosa González, Laura Elena; Cupul Magaña, Amílcar L.; Medina Rosas, Pedro; Calderón Aguilera, Luis E. (2013-07-24). "Estructura comunitaria de corales zooxantelados (Anthozoa: Scleractinia) en el arrecife coralino de Carrizales, Pacífico Mexicano". Revista de Biología Tropical. 61 (2). doi: 10.15517/rbt.v61i2.11161 . ISSN   2215-2075.
  9. 1 2 3 4 Roder, Cornelia; Arif, Chatchanit; Bayer, Till; Aranda, Manuel; Daniels, Camille; Shibl, Ahmed; Chavanich, Suchana; Voolstra, Christian R (2013-08-08). "Bacterial profiling of White Plague Disease in a comparative coral species framework". The ISME Journal. 8 (1): 31–39. doi:10.1038/ismej.2013.127. ISSN   1751-7362. PMC   3869008 . PMID   23924783.
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