Bryozoans are particularly common at water-depths between 20 and 80m where they feed on the abundant phytoplankton associated with this zone. Relatively few recent bryozoans are intertidal since the high wave-energy and problems associated with desiccation are too great for such delicate organisms.
Bryozoans living in shallow-water tend to be encrust the substrate. Shallow water forms tend to be more common on ephemeral than long-lasting substrates. Examples of ephemeral substrates include dead shells and seaweeds. They are less common on stable substrates because they are usually out-competed or out-lived by dominant competitors such as corals.
Bryozoans living in shallow-water are often erect: they stand up from the substrate. This gives the organism improved access to feeding grounds above the sea floor where there may be increased competition for food resources. Erect forms in shallow water may be flexible, which are better adapted to withstand current actions. Small, discoidal to cap-shaped unattached bryozoans have been successful in colonising shallow mobile sandy sustrates.
Author: Luke Mander
Last updated: 20.11.05
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