Friday, March 23, 2012

Sea Anemones - Flowers of the Sea

On February 20, 2012,  Faroe Islands Post issued the stamp set feature Sea Anemone , Flower of the sea. The issues consist of 4 postage stamps depicted colorful sea anemone and designed by Ingi Sørensen . Sea anemone are related to jellyfish and corals, all of which have a relatively simple circular body shape with numerous tentacles surrounding a mouth at one end of the organism
Marine biologists consider difficult to determine the species of sea anemones. Conservation of this animal group requires special methods and specialist knowledge is required to ensure correct identification. Although the sea anemone fauna in the Faroese area is not yet completely documented, Thirty species of sea anemone have been identified in the Faroes, but the total number of species is presumably higher.

Since the anemone lacks a skeleton, the contractile cells pull against the gastrovascular cavity, which acts as a hydrostatic skeleton. The anemone stabilizes itself by shutting its mouth, which keeps the gastrovascular cavity at a constant volume, making it more rigid.

Sea anemones’ shapes and colours give them a striking appearance reminiscent of exotic tropical plants, which also inspired their name and overall scientific classification, Anthozoa.
Despite their flower-like appearance, most sea anemones are predators. They are predatory animals, which paralyse their prey with stinging nematocysts which fire a harpoon-like structure which delivers a dose of neurotoxins. They have numerous poisonous cells on their surface . The poisonous cells paralyse prey, after which it is captured and transported through the sea anemone’s mouth and into its intestinal cavity, where it is digested.   To eat the fish, or crustacean, they move the prey into their stomach. Anemones are sessile (stay in one spot), but they can move if necessary.

Sea anemones are found in all oceans and at all depths, from just below the water surface to depths of more than 10,000 metres. Many species are found on wharfs and rocks at the water surface, where they add colour to the more neutral blue-green or brown surroundings – one of the reasons that most people with a relationship to the sea are fond of them.

Sea anemones reproduce both sexually, with sperm and eggs, and asexually, typically through pedal laceration, in which a small piece of the pedal disc breaks off. This piece then develops into a new sea anemone that is a clone of the mother.
The size of Faroese sea anemones varies greatly. The diameter of fully grown sea anemones varies from more than 30 centimetres for the largest species, Bolocera tuediae, down to a couple of millimetres with Edvardisia danica. The longest species in the Nordic seas is the very common Frilled Anemone (Metridium senile), which can reach lengths of a half metre.

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