Bryozoans

Bryozoan / Class - Cheilostomata / Phylum - Ectoprocta

Bryozoan / Reteporellina sp. / Family - Phidoloporidae

Bryozoans are tiny animals that form coral-like colonies. Because many bryozoan colonies form hard, limestone skeletons they are often confused with corals. In fact, the individual bryozoan animals (zooids) are much smaller and more complex than coral polyps.

Not all zooids in a colony are the same. Some provide support for the colony. Others are designed for feeding, cleaning and protecting the young.

Physiology

Bryozoan colonies come in a wide range of forms and sizes varying from plant-like forms to flat sheets. Some, the so-called 'lace corals', look like small corals.

Habitat

The majority of bryozoans live in the sea, others live in fresh and brackish water.

Bryozoans are often among the first animals to settle and grow on bare patches of the reef. As a result they play an important part in cementing reefs with the limestone from their skeletons a source of reef sediment.

Bryozoans on coral reefs form relatively small colonies and occur in environments such as caves and under coral plates. Therefore, they are difficult to see, although divers often photograph some, such as the 'lace corals'.

The Great Barrier Reef contains an estimated 300-500 species of bryozoans, about 8-12% of the world's species.