Subtidal coarse sediment

Undersea beds of coarse sand, gravel and shingle

Close to the shore, coarse sand, gravel and shingle seabeds are found on the open coast or in tide-swept marine inlets.  These areas are disturbed by waves and tides, which prevent finer sands and mud from settling. 

Most of the animals that live here are found buried in the seabed – the safest place to be. Even as the water becomes deeper, most of the life remains beneath the surface, and the animals found there include bristleworms, sand mason worms, small shrimp-like animals, burrowing anemones, carpet shell clams and venus cockles. Small varieties of calcareous algae may also live on fine gravels.

In much deeper water, coarse sand and gravel or shell fragments may cover large areas of the continental shelf.  At present, little is known about its ecology, due to the technical difficulties of exploring deeper water.

For the official habitat definition please see the documents listed below.


European distribution

Widespread around the British Isles and mainland Europe.


Official habitat definition

EUNIS habitat A5.1 Sublittoral coarse sediments


Further information

JNCC Marine Habitat Classification - Infralittoral Coarse Sediment

JNCC Marine Habitat Classification - Circalittoral Coarse Sediment

JNCC Marine Habitat Classification - Offshore Circalittoral Coarse Sediment

JNCC EUNIS habitat correlations table

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