Video of a sponge reef taken in the Strait of Georgia, May 2008.
Greeen laser points are 10 cm apart.
Sponges are sessile animals that filter water through their porous bodies, and ingest food particles and dissolved materials. There are more than 7000 species alive today living in both freshwater and marine environments, and are the oldest known multicellular animals.
The sponge skeleton consists of spicules made of different materials, and sponge species are categorized by their spicule type: