Sand beach

They are wonderful

Wave exposure can for example vary along different coastlines, on different beaches and even along the same beach. Furthermore, dehydration, particle size, organic and oxygen content vary at different depths within the bottom sediment. All these factors facilitate an abundance of environments and therefore a wealth and variety of living creatures along sand beaches - in spite of what may on the surface appear, lifeless.

The art of digging

Those organisms that live on sandy bottoms, and can dig down into it, have several advantages. For example::

Hide from their enemies.

Protection from dehydration.

Less risk of being washed away.

Increased possibilities of finding food.

    Most of the larger creatures exploit some form of physical attribute in the sand that can make digging easier. You have certainly noticed that when you tread on wet sand, how it becames drier, harder and lighter in colour. When the water content of the sediment weighs less than 22% of the total weight, and it is compressed, its structure changes. The water does not fill the spaces between the sand grains anymore. The sedimentet becames hard and resistant.


Instead of compressing the sand with your foot make small light movements in the sand that has more than 25% water, the sediment becames softer and less viscos (quicksand). When, under these circumstances the sediment is exposed to pressure, its structure changes, and a sludge of water and sand grains is created. This phenomenon is known as tixotropi.    

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Waves, bottoms and construction

Sand movement and erosion

Sand bottoms as living environments

The art of digging

Sand beach organisms

Food web

Change and variation

Swedish beach life

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Bo Johannesson | Martin Larsvik | Lars-Ove Loo | Helena Samuelsson