What may come as a surprise to some is that the Neptune Grass (Maltese: Alka/ Posidonja) is actually a flowering plant. Interestingly, this sea grass is an endemic of the Mediterranean Sea and is known by the scientific name of Posidonia oceanica. The genus name Posidonia was termed after the Greek god of the sea Poseidon, whilst oceanica refers to its former wide distribution.
The Neptune Grass is a long-growing submerged seagrass with bright green long ribbon-like leaves which turn brown with age. Under these leaves are fibrous tufts which are actually the remains of previous leaves. In spring green and inconspicuous flowers are borne on stout stalks, which upon fertilisation form olive-shaped fruit.
The meadows of Posidonia provide a very important habitat, which apart from providing food for numerous species, are also an important breeding ground, and are considered as an effective natural means against coastal erosion. In addition, the shed Posidonia leaves which are deposited on the seashores by wave action forming banquettes support an array of terrestrial and marine creatures such as amphipods, snails, spiders and others.
The Posidonia beds are considered to be a priority habitat of importance at European level and are protected both at regional and local level. According to a study commissioned by MEPA, the Posidonia beds found in our territorial waters have a good conservation status; that is the population dynamics and habitat are such they should maintain the population on a long term. In addition, MEPA is helping to safeguard this important species and its habitat through the designation of Marine Protected Areas.