Hello, my name is Posidonia.
Holidaymakers or nearby residents, do you know who I am?
Apparently, you don’t. Very often, you criticize me and complain about me to your elected representatives.
Let me introduce myself. My scientific name is POSIDONIA OCEANICA, commonly known as Posidonia. Consisting of roots, stems and leaves, I am a flowering sea plant, bearing fruits periodically.
If you look underwater, you probably got a glimpse of my elongated green-leaf hair swaying at the mercy of the waves. These tufts are called Posidonia Herbarium. My leaves dry out and are carried by the current, ending up as brownish heaps on the beach. In these masses, you can also find small fibrous balls that I lose in the autumn and which have been washed away by the sea. These natural elements prove the good health of the sea underwater world.
You can find me all along the Mediterranean basin, as an almost continuous thin border that can be observed from 0 to 35 meters’ deep. However, the size and health of this aquatic plant habitat must not live my fragility down. I do suffer a lot from the mechanical action of boat anchors and fishing trawls which tear off my rootstocks (called rhizomes) and I am very sensitive to sea water quality. My life deteriorates facing coastal development and pollution.
To make a comparison, I would say that the Posidonia Herbarium is the equivalent to our forests. My leaves produce an important part of oxygen which is vital to marine life (10 liters per day per m2). For sea animals (sea urchins, fish), this aquatic plant represents a shelter, a breeding-ground and constitutes their main source of alimentation. The first link of the food chain leading to the Human Being is these animals. You can probably understand now why I belong to the protected species on a national level.
You may also want to know that Posidonia Herbarium protects the coast and the beaches against erosion. Thanks to the density of my leaves, I slow the undercurrent and I absorb the strength of waves on the shore. As my leaves and stems trap the sediments brought in by ocean currents, I preserve the ocean bed like a tree preserves the ground soil. All the sediments on the shore help to protect our shores against the action of the sea. They form a cover which keeps the sand and protects the beach against sea blows. This is the reason why the village of Le Pradet keeps them on the beach as long as possible and, even if there is still a little left, even if I stick to your skin, I am not as dirty as you might think. I think that the water quality of the village is good and that I am here to protect what you wish to find next year for your holidays : a nice beach. So, enjoy your swim !
(Valerie Besio)