Natural England - Intertidal mixed sediments

Intertidal mixed sediments

Seashores made of a mixture of stones, gravels, sands and mud.

Intertidal mixed sediments © JNCC

Intertidal mixed sediments © JNCC

Mixed sediments are comprised of unsorted pebbles, gravels, sands and mud, and they may also include rocks and a few large boulders. This type of shoreline tends to occur in more sheltered locations, and is not found where there is strong wave action.

With such a broad range of seabed types on a single shoreline, the animal and plant communities are very diverse. Brown and green seaweeds can live on the larger rocks, and barnacles may also be abundant on any hard surfaces.

Animals living on or in the sand and mud or between the pebbles include many worms such as ragworms, mud shrimps and sandhoppers, cockles and other bivalve shells, as well as the spire shell snail.

This habitat is very vulnerable to physical disturbance such as bait digging as it takes a long time to recover.

Brief description of European distribution

This is an uncommon broad habitat, found at a few scattered sites in the British Isles – in the south-west and north-east of England, East Anglia, west Wales and in north-western Europe.

Further information sources

Littoral mixed sedimentexternal link (JNCC)

Littoral mixed sedimentsexternal link (MarLIN)

Interesting fact 

Because these shores have many different types of habitat, there is a wide variety of wildlife living there.