Natural England - Subtidal mixed sediments

Subtidal mixed sediments

Undersea beds of a mixture of stones, gravels, sands and muds.

Subtidal mixed sediments © Lin Baldock

Subtidal mixed sediments © Lin Baldock

As the name suggests, mixed seabeds can have a range of different types of sediment from muddy, gravely sands to mosaics of cobbles and pebbles in or on a sand, gravel or mud seabed. Mixed areas also include seabeds where waves or ribbons of sand form on the surface of a gravel bed.

Because mixed seabeds are so varied, they may support a wide range of animals, both on and in the sediment.  Animals found here include worms, bivalves (with their paired, hinged shells), starfish and urchins, anemones, sea firs and sea mats.

Brief description of European distribution

This broad habitat is widespread around the British Isles and in Europe.

Further information sources

Sublittoral sedimentexternal link (JNCC)

Sublittoral mixed sedimentexternal link (JNCC)

Infralittoral mixed sedimentexternal link (JNCC)

Circalittoral mixed sedimentexternal link (JNCC)

Offshore circalittoral mixed sedimentexternal link (JNCC)

Interesting fact 

On mixed seabed that are not too disturbed by waves or the tides, plant-like hydroid animals may attach to large stones or shells amongst the otherwise soft sediment.