Kelp Encrusting Bryozoan
Author:Â Madeleine Dorion
Photo by D. Young
Common Name: Kelp-encrusting Bryozoan, Kelp Lace Bryozoan, White Encrusting Bryozoan, Coffin Box. Many of the bryozoans are referred to as “moss animals”.
Scientific Name:Â Membranipora serrilamella (formerly known as Membranipora membranacea).
Membranipora serrilamella get their more common name, Kelp-Encrusting Bryozoa, for fairly obvious reasons. They grow on/encrust kelp with a white or silver crust that grows in circular patches. Each of these circular patches are constructed by lots of tiny rectangular boxes, each containing the zooid which are the individuals that make up the colony. The crust may only be up to 1mm in height.
The colony begins with an individual and then grows in a radial pattern outwards from the edges to create a colony containing hundreds of zooids. Sometimes colonies do not get along, in which case, they will compete for space.
Kelp-encrusting Bryozoa can grow in waters up to as deep as 180 meters but are commonly found in the deepest kelp forests up to the surface. Around Victoria, British Columbia, they are often found growing on the float or blades of Bull Kelp (Nereocystis luetkeana). In addition to growing on kelp it is often on other solid surfaces such as docks and rocks. It’s annual burst of growth occurs during summer months and during this time it can grow several millimeters in diameter per day. By the end of the summer some kelps are completely engulfed by a white crust.