Posidonia is not an algae but a flowering plant consisting of bundles of leaves grouped on rhizomes (underground stems).
It forms underwater meadows called seagrass beds, located just below the surface and down to approximately 40 meters deep.
It is endemic to the Mediterranean.
Occupying an area of 1 to 2% of the seabed, seagrass beds harbor nearly 25% of Mediterranean biodiversity.
The seagrass bed constitutes the basis of the richness of coastal waters and serves several roles:
Posidonia is an essential plant for the planet: every day, it purifies the water by absorbing atmospheric carbon dioxide.
Video produced by Andromède Océanologie for the Corsican Environmental Agency