Aquascope Facts
Cliff and rocky beach ecology

Protection against predators

<A HREF="">[Watch a opisthobranch eating 1,3 MB]</A>
Opisthobranchs eating hydroids which try to protect themselves with their stinging cells .

Like plants, attached creatures are unable to flee from their predators. This can result in the development of a physical or chemical defence mechanism. Thorns and a hard casing can be protection enough, but poisons and bad tasting substances are also used. Certain attached organisms have such good protection, they are almost never preyed upon, but in certain cases, predators have adapted and can penetrate protective measures. This is the case when nudibranchs prey upon certain cnidarians or sea-mats.
    In many cases, protective measures also have a cost. To produce protective structures or chemicals demands energy and material, therefore, certain creatures develope some form of protection only when they are attacked. This is the case with certain sea-mat colonies that develope thorns within a couple of days after being attacked by a predator.
Polycera quadrilineata on Membranipora 15 kB
The opisthobranch Polycera quadrilineata, about 3 cm long, feeding on the sea-mat Membranipora membranacea.

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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