2. Données et outils
  3. Rechercher un habitat
  4. MA6-51 - Assemblages des vases et sables vaseux supra- et médiolittoraux en biocénose lagunaire et estuarienne en Méditerranée
  5. Description
MA6-51 - Assemblages des vases et sables vaseux supra- et médiolittoraux en biocénose lagunaire et estuarienne en Méditerranée

Assemblages of Mediterranean littoral muddy sands and muds in lagoons and estuaries biocenosis

Classification des habitats EUNIS 2022

Descriptif de l'habitat

Present in the mediolittoral stage and the upper part of the infralittoral. The banks are relatively stable, but the beds change with the violent winter flooding. Sediment is formed of fine sand, muddy sands and mud according to the course of the river bed. Surface salinity is low (0.03 to 2,5 for the Rhône) whereas that of the deep layer, in contact with the benthic fauna, is much higher (16 to 21 for the Rhône). A marine salty patch can be seen sunk underneath the fresh water of the river. Tides are weak and only cause minor changes in the water’s chlorinity. The winds have a more marked influence on the position of the salty patch. When parts of the estuary or the estuary lagoons are cut off, either naturally or by human action, the salinity of the water may increase considerably.
Population variations are linked to the topography of the bed, which causes a differential distribution of the various types of sediment, and to anthropic action. These are especially reflected in the size of species populations, which varies with granulometry but can also be greatly reduced when anthropic action is too great. In the absence of the tide effect, the transition is rapid between the (freshwater) limnic environment and the marine environment. Thus there is no gradient in the distribution of the fauna, which occurs patchily. The species present are characterised by very rapid cycles of development that permit accelerated reconquest of the environments.

Bibliographie

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