An effective way of losing heat is to let water evaporate, but this also can dehydrate the organism. Certain organisms collect so much water as possible between their shell and body before they are left stranded at low tide. Barnacles do this, so they are able to give off heat by means of evaporation.
To breath air
To conserve water at low tide, certain mussels, shellfish and barnacles must enclose themselves totally within their shells. At such times they can enter a trance state, where they do not even need oxygen from the surrounding water.
|Cliffs and rocks are fantastic!|
|Zoning and flecked occurrence|
|Animals that are attached|
|Variation and change|
|Variations in water level|
|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|