Unlike many sponges which are reduced to a mat of loose spicules once their organic matrix has decomposed, dead hexactinosan sponges retain their shape as they are buried by clay-rich sediment. This burial process protects the siliceous skeletons from dissolving in sea water. Building on the skeletons of previous generations, live sponges can be over a metre high. These sponge reefs are a key to the past, to unlocking the secrets of the life and times of the largest bioconstructed organism ever to live on earth. And we know very little about them.
Countless questions remain to be answered.
No one knows what extraordinary secrets remain hidden in the heart of the ocean. Lynn Lee is the Haida Gwaii local coordinator for the World Wildlife Fund.