They’re called cloud sponges (Aphrocallistes vastus) but they only look fluffy. Press hard on one – and it will collapse in your hand like a meringue. These single-cell animals, which tend to form vase-like structures, can become huge, and are made of tiny, interlocking pieces of glass (silica).
Ok, let’s get the animal thing out of the way because I know what you’re thinking: “How on earth could this be an animal? It doesn’t have a mouth, it doesn’t have eyes, and now you’re telling me its body is made of glass?!”
Yuppers. You better believe it. Furthermore, you better believe Aquarium biologist Justin Lisiango who says, “No one knows how they produce their glass skeletons out of nothing but water. They grow to limitless proportions and filter nutrients out of seawater to feed themselves.”
He regularly heads out to Howe Sound with the Vancouver Aquarium’s Howe Sound research divers to collect data and monitor the health of the animals living there. Justin says that at one of their dive sites there are at least a thousand cloud sponge that form a sponge garden.
These sponge gardens act as nurseries for juvenile rockfish, giving them a place to hide and find food. Often, peeking inside a cloud sponge opening can reward Justin with the sight of one of these young rockfish looking back at him.
Justin says even though scientists know that these sponge gardens are an integral part of our local ecosystems, they still know very little about the natural history of the cloud sponges that make them up.
“We don’t know how fast they grow, how they reproduce or what specific conditions they need to thrive.”
Cloud sponges are usually found at depths of over 60 metres but we’ve made it easy for you to see them in the Treasures of the BC Coast gallery here at the Aquarium.