Posidonie

The posidonies , (kind Posidonia ), although they live under water, are not Algue S, but of the plants to flowers (Angiosperme S) Monocotylédone S underwater, of the family of the Posidoniacée S. Like all the plants with flowers, they have root S, and reproduce thanks to the Fruit S which they produce.

There are 9 species:

Posidonia angustifolia Cambridge & J.Kuo (1979)
Posidonia australis Hook.f. (1858)
Posidonia coriacea Cambridge & J.Kuo (1984)
Posidonia denhartogii J.Kuo & Cambridge (1984)
Posidonia kirkmanii J.Kuo & Cambridge (1984)
Posidonia oceanica (L.) Delile (1813)
Posidonia ostenfeldii Hartog (1969)
Posidonia robertsoniae J.Kuo & Cambridge (1984)
Posidonia sinuosa Cambridge & J.Kuo (1979)

8 species are on the Australian coasts. The ninth, Posidonia oceanica , is endemic the Mediterranean.

Posidonia

Drawing its name from the Greek god of the sea Poséidon, it plays several fundamental roles for the littoral seamen circle.

The herbaria which it form are places of spawning ground and nursery for many animal species. It also constitutes a source of food, sometimes important, for certain herbivorous species (sea urchin S, saupes, etc). Part of the production of sheets of an herbarium will be found exported, in the form of litter, worms of other distant ecosystems (beach, underwater canyon,…) where it will constitute an important source of carbon for the operation as of these ecosystems. It makes it possible to fix sea-beds thanks to the interlacing of its Rhizome S. Those pile up one year on the other, contributing to increase gradually the level of the bottom (approximately a Mètre by Siècle. It " piège" suspended particles and sediment, thus contributing to the maintenance of the clearness of water. The herbaria with Posidonia oceanica are regarded as essential formations in the storage of atmospheric carbon and the oxygenation of the medium.

Characteristics

reef barrier

When the herbaria of posidonie develop with the bottom of splits very low depth, the plants level surface and can create a reef barrier, contributing to the formation of a particular Biotope.

leashes of sea

The movements of the sea tend sometimes to lacerate the dead sheets and to gather them in balls of the size of a table tennis ball or tennis which one frequently finds on the Plage S.

protection of the littoral

The dead sheets of posidonies are often brought back on the edges of beaches, where they pile up, forming compact and imputrescibles heaps sometimes. These heaps then prevent the erosion of sand by the waves. Nevertheless, like these beaches, naturally protected, are not favourable with the development of the Tourisme, the Municipalité S often make them withdraw, thus exposing the littoral to the whims of the sea.

The posidonie belongs to five protected spaces on the French Mediterranean coasts, just like the black Oursin, the Grande mother-of-pearl, the brown mérou and the Cigale of sea.

External bonds

Scientific Grouping of interest of Posidonie

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