Aquascope Facts
Cliff and rocky beach ecology

Protection againts dehydration

Dried Porphyra and Littorina
This periwinkle has been enclosed in a dried leaf from the red alga of the species Porphyra. Both the periwinkle and the alga endure being out of the water for prolonged periods of time very well. The periwinkle avoids dehydration by simply closing its shell. The alga cannot stop the loss of water, but survives anyway, in spite of losing most of its water.
    Immediately after the water level has decreased and Marine organisms are left stranded in the air, they begin to lose water. To be able to survive in the beach zone, creatures must have organs and tissues that can endure water loss, or have mechanisms that prevent or minimize the loss of water. These mechanisms can be protective body parts, a certain type of behaviour, or both.
Those organisms, for example, rock lice, that have the ability to move, are able to avoid dehydration in a very good way. They simply move to an area that is moist. Such areas would naturally be underwater, but even crevices and cavities amongst the cliffs and rocks or under rocks and algae, in fact anywhere with a low rate of evaporation. Protection against dehydration and certain predators, e.g. birds, means that nearly all organisms, even the attached, are common in these micro-environments, but whilst competing for space, not all organisms will be able to find a refuge. Furthermore, it can be too dark for a great many algae.
    Many beach living organisms have a physique and special organs that help to protect them against dehydration. The common mussel and barnacle for example, protect themselves by enclosing themselves in their thick shells. Many shellfish have a lid with which they close the aperture of their shell.

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