MB2-522 - Ecomorphose du récif barrière de l'herbier de Posidonia oceanica

Ecomorphosis of "barrier-reef" Posidonia oceanica meadows

Classification des habitats EUNIS 2022

Descriptif de l'habitat

In the Posidonia beds of sheltered bays, the vertical growth of the rhizomes leads to a slow rise of the matte that enables the meadow to reach the surface; this structure is called a ‘fringe reef’. Between the emerging front of the reef and the coast, conditions become unfavorable (great variations in salinity and temperature), and the meadow dies, leaving a sort of ‘lagoon’ cut off from the open sea by a ‘barrier reef’. This lagoon is usually occupied by small magnoliophytes (Cymodocea nodosa and Zostera noltei) developing on dead matte.
At the level of the barrier reef, which can be up to several meters wide, the leaves emerge and spread out on the surface of the water, particularly in spring and summer. The reef extends in a gentle slope out to sea, where it constitutes a meadow with a continuous base.
The classic form of these reefs, with their front parallel to the shore, is the most widespread; however, more extensive particular structures (reef platforms) have been observed in Sicily and Corsica and many typologies have been suggested.

Bibliographie

European Topic Centre on Biological Diversity 2022. EUNIS marine habitat classification 2022 including crosswalks. Table Excel. (Source)