More than a thousand meters deep in the ocean on the western Canadian continental shelf grow reefs of creamy white to bright yellow cup- and funnel-shaped sponges.  Although these sponges are found worldwide, they only form reefs in this area, which can be up to 21 meters thick and many kilometres wide. These areas appear to contain the special conditions the sponges prefer: glacier-scoured troughs with stable seafloors consisting of rock, coarse gravel, and large boulders.  The sponges are not able to anchor to muddy or sandy floors.

The sponges are formed from silica, the basis of both beach sand and glass, hence their name.  Their rigid reef formations are vital in providing habitat for many kinds of fish and invertebrates and may act as important nursery areas for these animals.  Because they have very little organic material in their make-up they do not have significant predators.  The siliceous skeleton accounts for 90% of their body weight.
 
They are filter feeders, directly absorbing dissolved substances and to a lesser extent particulate matter.  They have an electrical conduction system across their bodies which allows them to sense disturbances such as physical impact or too much sediment in the water.  Their immediate response is to stop feeding for about 20 to 30 minutes.  If the irritation is still present when they resume feeding, they will stop again.

These sponges grow up to about 7 centimetres per year and can live up to 220 years, perhaps longer.  Little is known about how they actually reproduce. However, larvae are formed which settle amongst the rigid skeletons of previous sponges, using this framework to grow upon and expand.  Radiocarbon dating of reef cores has estimated these reefs as being between 8500 and 9000 years old.  Thus, they have often been referred to as examples of “living fossils.”

Threats to this species:  Industrial fishing can cause devastating damage to the reefs, especially bottom trawling and dredging.  Trawling involves dragging across the ocean floor large nets which are attached to two otterboards weighing two tonnes that hold the nets open to capture the fish.  These trawl tracks can leave a trail of shattered sponges. Hook and line fishing can also impact the reefs as the gear is often dragged along the seafloor and can potentially break the sponges.  If the sponges are removed from the floor, there is no longer a framework for future sponges to grow upon.  It has been estimated that broken sponge reefs may take up to 200 years to recover.

Another concern is offshore oil and gas exploration.  As a moratorium on exploratory drilling has been lifted in Hecate Strait and Queen Charlotte Sound by the BC government, the oil and gas companies have leases in the reef areas.  Not only can actual drilling in these areas cause significant damage to the reefs, but also drilling at a distance from the reefs may still cause impacts such as increasing the amount of sediment in the seawater or oil pollution.