Biodiversity

Introduction > Porifera > Cnidaria > Polychaeta > Crustacea > Mollusca > Bryozoa > Echinodermata

The members of the phylum Bryozoa are colonial invertebrates with many small individuals called zooids growing in many different forms such as runners, sheets, mounts, plates or trees. They are often mistaken for corals, sponges or even seaweeds. Bryozoan colonies arise from numerous asexually proliferated zooids. Each individual zooid is enclosed in a protective box-like exoskeleton, with apertures for ciliated feeding structures known as lophophores.

Bryozoans have been discovered in great numbers and in an amazing diversity of morphological forms in the deep-sea. In the deep sea they are usually sessile, active suspension feeders. There are some large forms but most are small, fragile and rarely collected intact. Bryozoans can be rigid, with fused zooids forming strong erect branched forms. Through to soft ctenostome forms which lack a rigid calcified exoskeleton. Ctenostome bryozoans are normally found on abyssal mud and illustrate how bryozoans have adapted to the deep-sea environment.