Intertidal Habitats

Muddy shores, salt marsh and mangroves


Salt marsh plants are located immediately adjacent to the sea and extend below the level of spring high tides. They are tolerant of high salinity and have fleshy or juicy stems and minute leaves. Two very similar, low, straggling bushes (Halocnemum, 48) grow on the upper shore while a small annual herb (Salicornia, 52) is found closest to the sea. The mud crab that produces burrows with raised mounds (47), is typical of these areas.

Black mangroves (50) are found on Qurma Island and amongst the creeks of Dawhat ad-Dafi. These small trees are living close to the most northern edge of their distribution. They are smaller than on the Red Sea coast because of the cold winter temperatures. They provide food and shelter to many small invertebrates including commercially important shrimp (55) and they act as a nursery area for many species of young fish including the Arabian killifish (54). Living in areas with muddy sediments means that there is little oxygen for the roots. The upward growth of 'finger-like' projections is an adaptation allowing the plants' roots to obtain oxygen directly from the air. The radiating root pattern plays an important role in stabilising the sediment and preventing the problems caused by coastal erosion. Salt is excreted from the underside of the leaves and can be seen as small crystals.

Below the mangroves the surface of the mud is often covered in a mat made up of a number of species of blue-green algae (51), where mud snails (46) can be found feeding in high densities. There are several types of crabs in this zone, some with blue claws and others with purple ones. Large burrows in this area are occupied by a predatory crab (49). The long thin tongues protruding from small volcano-like mounds are the mouth piece of a large worm-like animal which feeds on the organic matter on the mud surface.

Below the low tide level seagrasses (53) may again be found along with a portunid or swimming crab, easily recognised as the final pair of legs are flattened as paddles. They migrate inshore to feed during high tide. These rich muddy shores are an important area for numerous birds such as herons and waders which feed on small fish and crustaceans.



More pictures to muddy shores, salt marsh and mangroves:

Black mangroves / Barnacles and sponges on pneumatophores
Blue-clawed mud crab
Grey heron and reef heron
Blue-green algal mat
Swimming crab