Porites Stephensoni

''Porites'' is a genus of stony coral; they are small polyp stony (SPS) corals. They are characterised by a finger-like morphology. Members of this genus have widely spaced calices, a well-developed wall reticulum and are bilaterally symmetrical. ''Porites'', particularly '' Porites lutea'', often form microatolls. Corals of the genus ''Porites'' also often serve as hosts for Christmas tree worms ('' Spirobranchus giganteus'').

Aquarium trade

Specimens of ''Porites'' are sometimes available for purchase in the aquarium trade. Due to the strict water quality, lighting and dietary requirements, keeping ''Porites'' in captivity is very difficult.

Paleoclimatology

Porites corals have been shown to be accurate and precise recorders of past marine surface conditions. Measurements of the oxygen isotopic composition of the aragonitic skeleton of coral specimens indicate the sea-surface temperature conditions and the oxygen isotopic composition of the seawater at the time of growth. The oxygen isotopic composition of seawater can indicate the precipitation/evaporation balance because oxygen atoms of the more abundant mass 16 will preferentially evaporate before the more rare mass 18 oxygen. The relationship between temperature, precipitation, and the oxygen isotopic composition of Porites corals is important for reconstructing past climates, and associated large-scale patterns such as the El-Nino Southern Oscillation, the Intertropical Convergence Zone, and the mean state of the climate system.

Ecology and biogeography

Corals in the genus ''Porites'' are found in reefs throughout the world. It is a dominant taxon on the Pandora platform of the Great Barrier Reef. Potts et al. (1985) identified 7 dominant species: ''P. lobata'', ''P. solida'', ''P. lutea'', ''P. australiensis'', ''P. mayeri'', ''P. murrayensis'', and ''P. anae''. The oldest of six colonies in this reef was approximately 700 years old, and was estimated to be growing at 10.3 mm per year.

Meyer and Schultz (1985) demonstrated that ''P. furcata'' has a mutualistic relationship with the schools of French and white grunts (''Haemulon flavolineatum'' and '' H. plumierii'') that rest in their heads during the day. The fish provide it with ammonium, nitrates, and phosphorus compounds. Coral heads with resting grunts experience significantly higher growth rates and nitrogen composition than those without.

Representatives of this genus are found in both the Indo-Pacific and Caribbean basins.

Physiology

Some species in this genus demonstrate high levels of halotolerance. In the Gulf of Thailand ''P. lutea'' tolerates daily tidal shifts of 10-30‰ salinity. Moberg et al. (1997) determined that when the salinity declines, the symbiotic zooxanthellae decrease their photosynthesis rate as the coral contracts its polyps to protect them. The corals maintain their metabolic rate by temporarily switching to heterotrophy, consuming prey such as brine shrimp and other zooplankton.

''Porites'' growth rates can be determined by examining annual rings in their skeleton. This method was used to determine that ''P. astreoides'' grows its skeleton about the central axis by approximately 3.67mm/year, calcifies at approximately 0.55g/cm²/year, and increases density in this region of the body at approximately 1.69g/cm³/year. Additionally, Meyer and Schultz (1985) reported that coral growth varies seasonally. They observed that ''P. furcata's'' growth rate peaked between May and August, which is summertime in their Caribbean habitat.

Threats

Threats to corals in the genus ''Porites'' include predation, climate change, and anthropogenic pollution. When exposed to increased temperatures and copper, ''P. cylindrica'' slowed its rate of production. Additionally, the symbiotic zooxanthellae reduced their photosynthesis rate when exposed to both stressors.

Done and Potts (1992) observed that when settled, larvae in ''Porites'' are vulnerable to competition from other corals and predation from sea urchins. Additionally, mortality likelihood increases following strong storms.

Species

* ''Porites alveolata'' Milne Edwards, 1860
* †''Porites amplectans'' Felix, 1921
* ''Porites annae'' Crossland, 1952
* †''Porites anguillensis'' Vaughan, 1919
* ''Porites aranetai'' Nemenzo, 1955
* ''Porites arnaudi'' Reyes-Bonilla & Carricart-Ganivet, 2000
* '' Porites astreoides'' Lamarck, 1816
* ''Porites attenuata'' Nemenzo, 1955
* ''Porites australiensis'' Vaughan, 1918
* ''Porites baueri'' Squires, 1959
* '' Porites branneri'' Rathbun, 1887
* ''Porites brighami'' Vaughan, 1907
* ''Porites cocosensis'' Wells, 1950
* ''Porites colonensis'' Zlatarski, 1990
* ''Porites columnaris'' Klunzinger, 1879
* ''Porites compressa'' Dana, 1846
* ''Porites cribripora'' Dana, 1846
* '' Porites cumulatus'' Nemenzo, 1955
* '' Porites cylindrica'' Dana, 1846
* ''Porites decasepta'' Clareboudt, 2006
* '' Porites deformis'' Nemenzo, 1955
* '' Porites densa'' Vaughan, 1918
* ''Porites desilveri'' Veron, 2000
* '' Porites divaricata'' LeSueur, 1821
* '' Porites echinulata'' Klunzinger, 1879
* '' Porites eridani'' Umbgrove, 1940
* '' Porites evermanni'' Vaughan, 1907
* '' Porites exserta'' Pillai, 1967
* ''Porites flavus'' Veron, 2000
* '' Porites fontanesii'' Benzoni & Stefani, 2012
* '' Porites fragosa'' Dana, 1846
* '' Porites furcata'' Lamarck, 1816
* '' Porites gaimardi'' Milne Edwards & Haime, 1851
* ''Porites harrisoni'' Veron, 2000
* ''Porites hawaiiensis'' Vaughan, 1907
* '' Porites heronensis'' Veron, 1985
* ''Porites horizontalata'' Hoffmeister, 1925
* †'' Porites indica'' Duncan, 1880
* ''Porites latistellata'' Quelch, 1886

* '' Porites lichen'' Dana, 1846
* ''Porites lobata'' Dana, 1846
* '' Porites lutea'' Quoy & Gaimard, 1833
* †'' Porites macdonaldi'' Vaughan, 1919
* ''Porites mannarensis'' Pillai, 1967
* ''Porites mayeri'' Vaughan, 1918
* ''Porites minicoiensis'' Pillai, 1967
* '' Porites monticulosa'' Dana, 1846
* '' Porites murrayensis'' Vaughan, 1918
* ''Porites myrmidonensis'' Veron, 1985
* ''Porites napopora'' Veron, 2000
* ''Porites negrosensis'' Veron, 1990
* ''Porites nigrescens'' Dana, 1846
* ''Porites nodifera'' Klunzinger, 1879
* '' Porites okinawensis'' Veron, 1990
* ''Porites ornata'' Nemenzo, 1971
* ''Porites palmata'' Dana, 1846
* ''Porites panamensis'' Verrill, 1866
* †'' Porites pellegrinii'' Duncan, 1880
* ''Porites porites'' Pallas, 1766
* †''Porites portoricensis'' Vaughan, 1919
* '' Porites profundus'' Rehberg, 1892
* ''Porites pukoensis'' Vaughan, 1907
* ''Porites randalli'' Forsman & Birkeland, 2009
* †''Porites reussiana'' Ducan & Wall, 1865
* ''Porites rugosa'' Fenner & Veron, 2000
* ''Porites rus'' Forskål, 1775
* ''Porites sillimaniani'' Nemenzo, 1976
* '' Porites solida'' Forskål, 1775
* ''Porites somaliensis'' Gravier, 1910
* '' Porites stephensoni'' Crossland, 1952
* '' Porites superfusa'' Gardiner, 1898
* †''Porites superposita'' Duncan, 1880
* '' Porites sverdrupi'' Durham, 1947
* †'' Porites trinitatis'' Vaughan in Vaughan and Hoffmeister, 1926
* '' Porites tuberculosa'' Veron, 2000
* ''Porites vaughani'' Crossland, 1952
* †'' Porites waylandi'' Foster, 1986

References

{{Authority control

Poritidae
Cnidarian genera
Taxa named by Johann Heinrich Friedrich Link