Facies with Ficopomatus enigmaticus

Description (English)

The characteristic species of this association is the Annelid Ficopomatus enigmaticus. This polychaete, also known as Mercierella enigmatica, is a marine tubeworm that build extensive concretions formed of the mass of their calcareous tubes. From the surface of the sea to depths of 1-2 meters, the species adheres to hard substrates of all kinds and sizes, ranging from shells, reeds, piles, and quayside and dockside structures, to the hulls of ships. The species is particularly tolerant of variations in salinity, adapting to both oligohaline (low salinity) and hyperhaline (high salinity) waters. It can withstand high rates of eutrophication, and is sensitive to wave action and intense hydrodynamics. Ficopomatus reefs develop exclusively in brackish environments, where they form belts, barriers and reefs up to one metre thick and from a few dozen centimeters to several meters wide.
They may also be built in the middle of shallow brackish basins, and look like large mushrooms adhering to fragments of hard substrates (shells, branches, rocks, reeds, etc.), sometimes reaching the surface of the water. They may extend for hundreds of square metres and are produced by many generations of tubeworms all growing attached to one others.

Source: EUNIS habitat classification