Coral and User talk:Matthew: Difference between pages

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[[Image:BB61 USS Iowa BB61 broadside USN.jpg|thumb|300px|right|HMS ''Matthew'']]

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<br /><span style="font: italic bold large serif;">Matthew</span>

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{{Taxobox_classis_entry | taxon = '''[[Anthozoa]]''' </br>(Corals and sea anemones)}}

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''see [[Anthozoa]]''

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Lost items found. Paranormal Investigations.<br />

'''Corals''' are [[gastrovascular]] marine [[cnidaria]]ns (phylum [[Cnidaria]]; class [[Anthozoa]]) existing as small [[sea anemone]]-like [[polyp]]s, typically forming colonies of many individuals. The group includes the important [[Coral reef|reef]] builders known as [[hermatypic coral]]s, found in tropical [[ocean]]s, and belonging to the subclass [[Zoantharia]] of order [[Scleractinia]] (formerly Madreporaria). The latter are also known as ''stony corals'' inasmuch as the living tissue thinly covers a skeleton composed of [[calcium carbonate]]. A large scale coral is actually formed of many individual [[polyps]], up to a few millimetres in diameter, which are individual [[organism]]s. However they function as one organism by sharing nutrients via channels in the skeleton and are clones of each other, hence having the same DNA.

Consulting. Advice. Reasonable Rates.<br />

No Love Potions, Endless Purses, or<br />

Other Entertainment.

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== Keeping Up Appearances tables ==

The hermatypic corals obtain much of their nutrient requirement from [[symbiosis|symbiotic]] unicellular [[alga]]e called [[zooxanthella]]e, and so are dependent upon growing in sunlight. As a result, these corals are usually found not far beneath the surface, although in clear waters corals can grow at depths of 60 m (200 ft). Corals breed by spawning, with many corals of the same species in a region releasing [[gamete]]s simultaneously over a period of one to several nights around a full [[moon]].

Hi Mathew its Edito*Magic (also known as Chris C. Nichols)

Corals are major contributors to the physical structure of [[coral reef]]s that develop only in tropical and subtropical waters. Isolated corals exist even in cold waters, such as off the coast of [[Norway]]. The most extensive development of extant coral reef is the [[Great Barrier Reef]] off the coast of [[Queensland]], [[Australia]]. [[Indonesia]] is home to 581 of the world's 793 known coral reef-building coral species.

I know you were one of the people who agreed with me on the discussion page that one neat table with all the Keeping Up Appearances specials together would look better than several separate tables per episodes, littered all over the page. I’m glad that you can see sense like I can. Hopefully we can make Updown see sense aswell. Please join in the debate further on the [[Wikipedia talk:Television episodes]]. Thanks! [[User:Edito*Magica|Edito*Magica]] 21:38, 11 July 2007 (UTC)

==Coral types==

There are several other types of corals, notably the [[octocoral]]s (subclass [[Octocorallia]]) and corals classified in other orders of subclass [[Zoantharia]]: to wit, the [[black coral]]s (order [[Antipatharia]]) and the [[soft coral]]s (order [[Zoanthinaria]]). Extinct corals include [[Rugosa|rugose corals]] and [[tabulate coral]]. These two groups went extinct at the end of the [[Paleozoic]]. Most other anthozoans would be treated under the common name of "[[sea anemone]]".

==Geological history==

[[Image:Fossil Coral Heliophyllum.jpg|thumb|Fossil coral ''[[Heliophyllum halli]]'' from the [[Devonian]] of [[Canada]].]]

Although corals first appeared in the [[Cambrian]] period, some 570 million years ago, they are extremely rare as [[fossil]]s until the [[Ordovician]] period, when Rugose and Tabulate corals became widespread.

Tabulate corals occur in the [[limestone]]s and calcareous [[shale]]s of the Ordovician and [[Silurian]] periods, and often form low cushions or branching masses alongside Rugose corals. Their numbers began to decline during the middle of the Silurian period and they finally became extinct at the end of the [[Permian]] period. The skeletons of Tabulate corals are composed of a form of calcium carbonate known as [[calcite]].

Rugose corals became dominant by the middle of the Silurian period, and became extinct early in the [[Triassic]] period. The Rugose corals may be either solitary or colonial, and like the Tabulate corals their skeletons are also composed of calcite. The finest details of their skeletal structures are often well preserved, and such fossils may be cut and polished.

[[image:coral.bristol.750pix.jpg|thumb|Coral skeletons in a zoological display]]

Scleractinian corals diversified during the [[Mesozoic]] and [[Cenozoic]] eras and are at the height of their development today. Their fossils may be found in small numbers in rocks from the Triassic period, and they are relatively common fossils in rocks from the [[Jurassic]] and [[Cretaceous]] periods as well as the Caenozoic era. The skeletons of Scleractinian corals are composed of a form of calcium carbonate known as [[aragonite]]. Although they are geologically younger than the Tabulate and Rugose corals, the aragonite skeleton Scleractinian corals does not tend to preserve well, so it is often easier to find fossils of the more ancient Tabulate and Rugose corals.

At certain times in the geological past corals were very abundant, just as modern corals are in the warm clear tropical waters of certain parts of the world today. And like modern corals their fossil ancestors built reefs beneath the ancient seas. Some of these reefs now lie as great structures in the midst of [[sedimentary rocks]]. Such reefs can be found in the rocks of many parts of the world including those of the Ordovician period of [[Vermont]], the Silurian period of the Michigan Basin and in many parts of [[Europe]], the [[Devonian]] period of [[Canada]] and the Ardennes in [[Belgium]], and the Cretaceous period of South America and [[Denmark]]. Reefs from both the Silurian and [[Carboniferous]] periods have been recorded as far north as [[Siberia]], and as far south as [[Australia]].

[[Image:'Brain' coral.JPG|thumb|Brain coral off the coast of [[Belize]]]]

However, these ancient reefs are not composed entirely of corals. Algae and sponges, as well as the fossilized remains of many [[Echinoderm|echinoid]]s, [[brachiopod]]s, [[bivalve]]s, [[gastropod]]s, and [[trilobite]]s that lived on the reefs help to build them. These fossil reefs are prime locations to look for fossils of many different types, besides the corals themselves.

Corals are not restricted to just reefs, many solitary corals may be found in rocks where reefs are not present (such as ''Cyclocyathus'' which occurs in the Cretaceous period [[Gault clay]] formation of [[England]]).

As well as being important rock builders, some corals are useful as zone (or [[Index fossil|index]]) fossils, enabling geologists to date the age the rocks in which they are found, particularly those found in the limestones of the Carboniferous period.

== Environmental effects on coral ==

[[Image:Reef0484.jpg|thumb|A coral reef can be an oasis of marine life.]]

Coral can be sensitive to [[natural environment|environment]]al changes, and as a result are generally protected through environmental laws. A coral reef can easily be swamped in [[algae]] if there is too much [[nitrogen]] in the water. Coral will also die if the water temperature changes by more than a degree or two beyond its normal range or if the salinity of the water drops. In an early symptom of environmental stress, corals expel their zooxanthellae; without their symbiotic unicellular algae, coral tissues are colorless, revealing the white of their calcium carbonate skeletons, an event known as '[[coral bleaching]]'.

A combination of temperature changes, pollution, and overuse has led to the destruction of many coral reefs around the world. This has increased the importance of [[coral biology]] as a subject of study. Climatic variations, such as [[El Niño]], can cause the temperature changes that destroy corals.

Some coral species exhibit banding in their skeletons resulting from [[annual]] variations in their growth rate. In [[fossil]] and modern corals these bands allow [[geologist]]s to construct year-by-year chronologies, a kind of [[incremental dating]], which combined with [[geochemistry|geochemical]] analysis of each band, can provide high-resolution records of [[paleoclimatology|paleoclimatic]] and paleoenvironamental change.

== Uses ==

[[Image: Assorted_living_corals.jpg|thumb|Living corals underwater are more colorful than dead coral]]

[[Coral reefs]] are a great source of [[tourism]] for [[scuba]] diving or snorkelling, however this has conservational implications due to damage from removal or destruction of coral.

Ancient coral reefs on land are often mined for [[limestone]]. An example of this is the quarrying of [[Portland limestone]] from the [[Isle of Portland]].

Reddish coral is sometimes used as a [[gemstone]] especially in [[Tibet]]. Pure red coral is known as 'fire coral' and it is very rare because of the demand for perfect fire coral for jewellery-making purposes.

== References ==

* Schrag, D. P., and Linsley, B. K., (2002), Corals, Chemistry, and Climate. ''Science'' '''296 277-278'''.

== External links ==

* [http://www.aims.gov.au/pages/auscore/auscore-00.html Australian Coral Records Research Group]

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