Bryozoa

Bryozoa is a phylum of aquatic, colonial invertebrate animals commonly called bryozoans or moss animals.

Bryozoa is a phylum of aquatic, colonial invertebrate animals commonly called bryozoans or moss animals. They are filter feeders made up of many connected zooids, and most species live in marine environments, although some are freshwater. Their colonies often form calcareous or gelatinous structures attached to submerged surfaces. In Canada, bryozoans are found in both freshwater and marine waters and are used as examples of native filter-feeding invertebrates.

Classification and naming

Bryozoa is a phylum within the kingdom Animalia. The group is also commonly referred to as moss animals, and some older sources use the names Polyzoa or Ectoprocta.

Biology and colony structure

A bryozoan colony is composed of many small units called zooids, which are connected and function together. Individual zooids are small, but colonies can form visible encrusting, branching, or gelatinous growths. Many species build colonies with calcium carbonate skeletons or other protective structures.

Habitat and distribution

Bryozoans live in aquatic habitats worldwide. Most species are marine, while freshwater species are concentrated in groups such as Phylactolaemata. They are found on hard submerged surfaces such as rocks, shells, wood, and algae. In Canada, they occur in both freshwater and marine environments. Bryozoans share aquatic habitats with many other animals, including jellyfish, shrimp, squid, and abalone.

Feeding and reproduction

Bryozoans are filter feeders. They capture suspended particles, including microorganisms, from the water using a lophophore. They reproduce both sexually and asexually, and some freshwater species form durable resting structures called statoblasts.

Fossil record and ecological role

Bryozoans have an extensive fossil record, with many fossil species known. Ecologically, they help form benthic communities and serve as food for a variety of animals.