Intertidal coarse sediments

Seashores made of pebbles, gravels and coarse sand

Seashore made of pebbles, gravel and coarse sand © Amy Ridgeway

Coarse sediment shores are composed of small rocks, pebbles, and gravel, sometimes mixed with coarse sand.

This type of beach occurs between the tides on fairly exposed, open shores, where wave action prevents finer sand and silts from settling. On some shores, coarse sediments may be present on the upper parts of shore, whilst there is more stable sand on the mid and lower shore.

A characteristic of this seascape is that the beach material is highly unstable, as the shingle and pebbles are rolled around by the sea.   Few animals can survive in this environment, especially when it is coupled with being exposed to the air when the tide is out, so the shore is often devoid of visible life.  However, animals do live here and they are specially adapted to survive in the spaces between the shingle and gravel, where they will not dry out. Close inspection of gravely and shingle shores may reveal tiny, shrimp-like creatures.

These shores may change at different times of the year.  When the sea is calm in the summer, and the stones are not being rolled around, barnacles and seaweed may grow on the larger rocks.

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

 

European distribution

This is an uncommon broad habitat, found at a few scattered sites in the British Isles and in north-western Europe.

Pebble and Gravel Seashores Fact

 

Official habitat definition

EUNIS habitat A2.1 Littoral coarse sediment

 

Further information

JNCC Marine Habitat Classification

JNCC EUNIS habitat correlations table