Posidonia in the Balearics

Oceanic Posidonia


Oceanic Posidonia is an aquatic plant, endemic to the Mediterranean Sea, belonging to the family Posidoniaceae. It is not an alga because it has the typical characteristics of terrestrial plants – roots, stems and leaves of up to one meter long.

Posidonia oceanic forms underwater meadows with an incredible ecological importance. It feeds more than 400 species of underwater plants and 1,000 species of marine and plant animals that find food and protection in the meadows and are also used for gastronomic purposes.

They are organized in clumps of 6 or 7 leaves, finding the oldest ones on the outside and the youngest ones in the interior reproducing both sexual and asexual way by stolons.

This species is found only in the Mediterranean Sea occupying an area of ??approximately 38,000 km², thus becoming a key species of the coastal marine ecosystem. Some believe that posidonia on the beaches is considered a solid waste and that, therefore, it should be eliminated. On the other hand, others consider that posidonia could be used as composting material, although this is prohibited by the Italian law 748/84, which prohibits the use of “algae and marine plants” for the preparation of compost.

On the beaches, especially in winter, there are also brown “balls” of Posidonia fibers formed by the waves.

It lives between 1 and 30 meters deep and, exceptionally, only in very clear waters, it can reach up to 40 meters, with temperatures between 10 and 28ºC.

The main factors that threaten the oceanic Posidonia meadows are maritime works, the pollution of coastal waters, the generation of artificial beaches and removal of dead leaves that reach the beaches and the anchorage of boats.

These ecosystems, which occupy approximately half a million km², are in decline on a global scale, with an estimated loss rate of 1-2% per year (four times the rate of loss of tropical forests); in the Mediterranean, however, this figure rises to 5%. In addition, the slow growth of these plants (2 cm / year) and their scarce seed production make the losses irreversible, since the recovery of a pasture requires several centuries.

The Balearic Islands have an area of ??55,795 hectares of Posidonia meadow, of which 7,650 hectares correspond to the waters of Formentera. This translates into 76.5 million m² to protect only in Formentera.

Let’s take care of the posidonia, value our ecosystem and respect nature. It is a treasure that was born so that we can preserve it, appreciate it and enjoy letting itself be part of the wonderful beaches of the Mediterranean and of the beauty that we can admire under the sea.

Leave a Reply

Your email address will not be published. Required fields are marked *