Posidonia oceanica: a resource for everyone, don’t call it ALGAE!

Abundantly present in the depths of our seas, Posidonia is an aquatic plant that is endemic to the Mediterranean Sea and belongs to the Posidoniacee family.It has characteristics similar to terrestrial plants: it has roots, a rhizomatous stem and ribbon-like leaves that are up to one meter long and joined in tufts of 6-7. Posidonia blooms in autumn and spring and produces floating fruit commonly called “sea olive”.WHY IS IT SO IMPORTANT?It forms submarine grasslands of considerable ecological importance, constituting the climax community of the Mediterranean Sea and exerting notable action in protecting the coastline from erosion. Inside it live many animal and vegetable organisms that find nourishment and protection in the prairie.Posidonieto is considered a good bioindicator of the quality of coastal marine waters.HOW TO TREAT IT?According to the latest regional environmental laws, supported by strict national and European regulations in terms of environmental protection, no matter how annoying Posidonia may be, it is to be respected for its considerable importance in protecting beaches from erosion. Beached Posidonia leaves are considered solid waste and must therefore be disposed of.This plant material can be composted for the production of “green composted soil conditioner”.SO, WHAT CAN BE DONE?In the past the leaves were used as insulation in the construction of roofs, as bedding for livestock and in packing fragile materials; indeed the leaves also called “glaziers alga”. In pharmacology the leaves were used to treat inflammation and irritation. In some areas of the Mediterranean, the leaves are still used today in cattle feed. The possibility of using them, after particular treatments, for greenhouse fertilization and the production of biogas is currently being analysed [41]. Furthermore, after putting them through a sophisticated cleaning system, some companies have already started to reuse the leaves as padding in large beach cushions. A recent study showed that Poseidonia oceanica leaf extract, which contains various polyphenolic substances, can be used for food preservation because of its antioxidant and antifungal properties.CONCLUSIONhealthy beaches = beaches rich in Poseidonia!