Aquascope Facts
Cliff and rocky beach ecology The shore crab is an example of an organism that is found along cliffs, but is even more common on beaches composed of rocks and boulders. This is probably because it is easier for them to find a haven where they will not be washed away, taken by birds and that there is probably more food to be found.
   On peeble beaches, the wave energy is so great that even large rocks and boulders are sat in motion, so much so, that they are heard hitting and rubbing against each other. It cannot be so easy staying alive in a pestal and mortel. Therefore, peeble beaches are rather poor in fauna within the surge zone. Micro-organisms are however found here, thanks to their small size and quick rate of growth. These micro-organisms are difficult to see, but their presence is felt because the rocks can feel slimy and slippery. Occasionally the peebles can be coated with a fast growing alga that is larger.
    The waves damaging effect on beach living fauna is greatest when the waves are strong enough to move rocks and boulders. Organisms can get disorientated, especially when the topside of the rock has became the underside. On some beaches, especially those that have a low gradient, not so much damage is caused by the waves as they break on irregularities further out. Alot of the waves energy is also absorbed by small movements of the rocks.
Washed up stones Unmovable stones
The rocks in the left-hand picture have been thrown up by storm waves, which is seen by the white patches of dead encrusting algae. The rocks on the right are more protected from the waves. On and around them there are many living organisms. - The white patches are living barnacles.

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Cliffs and rocks are fantastic!
Zoning and flecked occurrence
Animals that are attached
Modular construction
Variation and change
Variations in water level
Wave exposure
Both cliffs and rocks
Freshwater and saltwater
Geography, climate and history
Organisms life cycles
Organisms effect on each other
Energy and the flow of material

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© Aquascope 2000   Tjärnö Marine Biological Laboratory, Strömstad, Sweden
Bo Johannesson | Martin Larsvik | Lars-Ove Loo | Helena Samuelsson