The tendrils of new sponges wrap around spicules of older, deceased sponges. The tendrils will later form the basal plate of the adult sponge that firmly anchors the animal to the reef.

Deep ocean currents carry fine sediments that are captured by the scaffolding of sponge reefs. A sediment matrix of silt, clay, and some sand forms around the base of the sponge bioherms. The sediment matrix is soft near the surface, and firm below one metre deep. Dead sponges become covered in sediment, but do not lose their supportive siliceous skeleton.