Modern Forms

Bryozoans are abundant in all oceans and reach maximum diversity in the western Pacific. They are found at all water-depths, from the shoreline to the abyss. The deepest record of a living bryozoan is 8500m, but their importance as a group declines with increasing water-depth. Bryozoans are sensitive to their enviroment and the principal controls on their distribution are:

• Temperature - A few species are eurythermal but most have restricted temperature ranges
• Wave Action - Fragile colonies are likely to be damaged by strong wave action
• Sediment Supply - Most bryozoans are intolerant of high sedimentation rates, which may lead to the damage/clogging of their delicate feeding apparatus
• Substrate - Most bryozoan larvae require a hard substrate on which to settle. This limits depth ranges of bryozoan species, since deep sea sediments are often oozy muds, which offer little potential for firm anchorage
• Salinity - Most bryozoans require normal salinity levels, though there are a few euryhaline forms such as Bowerbankia, which can withstand salinities of just 20ppm

The three principal classes of bryozoan are living today - they are extant organisms. One species of bryozoan, Bugula neritina, is of current interest as a source of cytotoxic chemicals, bryostatins, which are under investigation as anti-cancer agents. Growth pattern and form of a bryozoan is an expression of its ecological niche rather than its classification. Therefore it is appropriate to describe the characteristics of modern bryozoa found in different ecological niches.

• Characters/ anatomy
• Major subgroups in the phylum
• Fossil record
• Modern forms
• Literature and web links
• Homepage

Author: Luke Mander
Last updated: 20.11.05
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