SANDY SEABED

At first sight the sandy seabed may appear to be a barren and uninviting environment capable of supporting very little life.

However, on closer inspection, it becomes clear that it's actually home to a wide variety of specially-adapted creatures using a series of highly unusual techniques to survive.

Some live their lives permanently beneath the sand, burrowing themselves away from danger while others remain on the surface but use incredible camouflage to blend in perfectly with their surroundings.

Grains of sand are actually made up of the ground down remains of pebbles which, in turn, were formed from much larger boulders.

These rocks began life as parts of huge cliffs which have collapsed into the sea or were washed into the oceans from adjoining rivers.

Over countless centuries these rocks are broken into ever smaller pieces which are ground down by the action of the waves pounding relentlessly against them.

Other hard objects like discarded shells can also be worn down to produce smooth, tiny grains.

Although from a distant most beaches appear to be one colour when you pick up handful of sand and look closely you will see that it's actually made up of many different shapes and colours.

Most species that live in or on sandy seabeds need to use camouflage or other ways to hide themselves in an environment which offers few hiding places either for the hunters or the hunted.

Sand eels spend much of their time hunting above the seabed, however, at the first sign of danger, they dive back into their sandy hideaways.

Masked crabs spend the daylight hours hidden several inches down in the sand with only their elongated antennae sticking up above the surface.

Many species of shellfish - like the Razor shell, the thin Tellin and the Sand Gaper - spend their lives buried in the sand with long siphons, often twice their body length or more, sticking up above the sand to allow them to breathe and feed.

Britain's most dangerous fish - the Lesser Weaver - buries itself below the sand with only its head and poisonous spines protruding above the surface. When alarmed they raise these venomous fins to protect themselves.

If trodden on by unwary paddlers they can inflict extremely painful wounds. There are even stories of fishermen cutting off their own toes because the agony of the sting is so intense!

Many species of bottom-living fish have evolved highly-specialised bodies to cope with their featureless habitat.

Not only have they developed camouflaged bodies to blend in with their surroundings they have also become virtually two-dimensional to reduce their chances of being seen.

Rays and skates are actually members of the same family as sharks - in fact they're flattened out versions of them - with certain crucial differences.

Because they spend much of their time motionless on the seabed their eyes protrude a long way above the rest of their bodies to ensure they can keep a close eye on what's going on around them.

With their mouths on the underside of their bodies they draw oxygen-rich water over their gills by means of specially-adapted holes - called spiracles - behind their eyes.

Ray and skate bodies are flattened from top to bottom and they lie on their bellies, however true flatfish have become squashed from side to side and this has entailed some very unusual adaptations.

Flatfish like Plaice, Brill, Sole and Turbot begin life as normal-looking fish with eyes and fins on either side of their bodies. They even feed in mid-water.

However, within one or two months of hatching one of the fish's eyes begins to migrate towards the other one. At the same time one side of the body starts to develop colour and pigment while the other remains white.

Changes continue as the body becomes wider and flatter until the adult fish is virtually exclusively bottom-living.

For some reason almost all flatfish end up lying on their left side.