Coral Mystery pt.VIII Biology by Dott.ssa Margherita Superchi

 This is its identification card:
scientific name:    Corallium rubrum
phylum:         Cnidaria
class:         Anthozoa (Animal flower: from the Greek     “ἄυθος/anthos” flower, and “ζῷον/zoon” animal)
subclass:         Octocorallia
order:         Gorgoniaceae

The Cnidaria is divided into 4 classes, one of these being the Anthozoa class which comes in the form of a polyp and is in turn divided into 2 sub-classes, according to the number of tentacles:
Hexacorallia (6 tentacles or multiples of 6) include reef corals, found on barrier banks, and commonly called madreporaria, sea anemones, black coral and gorgonacea.
Octocorallia, this is the coral we work with: Corallium rubrum, Corallium japonicum and another 27 species of coral.

Anatomy of Red Coral

The anatomy of coral is relatively simple, and is composed of:
- polyp colonies
- skeleton
- external surface

Regarding the polyp colonies: the small polyps with eight tentacles live in colonies, inside the skeleton, and transmit information, sensations, food, etc. through a system of canals in the external surface.
Too simple? I can provide some additional data.
The small polyps are in contact with the external world. They live in the water and from water they receive nutrients but are also subject to its dangers: fish, parasites, storms, volcanic activity, this we have seen, correct? It is also the polyps that take nutrition from the water, the plankton, which they digest and that is used to increase the skeletal axis.
Then there is what for the sake of simplicity we have called the external surface of the polyps but that we must of necessity call by its true name: sarcosoma. What is this? The sarcosoma is the whole of the tissues that cover the axial skeleton just like a glove covers a finger. The skeleton therefore is made from an external secretion. The skeleton of coral is entirely mineralised as it is composed of calcium carbonate, crystallised in the form of calcite. Inside the skeleton there is a network of canals very similar to the circulatory system.
It is through this system of canals that all parts of the skeleton are fed and all information is passed to the entire colony of polyps.
In fact, if we try to touch a single polyp, even a peripheral one, the polyp recognizes danger and conceals itself from view by completely contracting within its cavity, as will all the polyps of the colony: indicating that the information is immediately filtered from polyp to polyp.
Therefore we cannot consider the polyps as living autonomously within a colony but as mouths through which the coral feeds and maintains contact with the outside world.
We have already mentioned the “Red Coral” research group composed of more than 20 Universities and Marine Biology Institutes from all over Europe. These scientists divided their research on coral into individual tasks and studies, to acquire more knowledge, until then very limited, on how it grows, reproduces and feeds.
One member who has done much in the sector of nutrition is the Naples Zoological Station “Anton Dhorn”, through the Ischia Section at the time directed by my dear friend Gianni Russo.
Dhorn retrieved colonies of coral from the sea and placed them in a tank. He then performed extensive studies on the opening and closing of the polyp colonies and noted that they all expanded, that is the polyps come out when they are hungry and re-enter the sarcosoma as soon as they are sated. One would think for a short nap...

to be Continued...
[text taken with license from the author Giuseppe Rajola from the book Sciacca Mystery]

Enjoy!