Biological patterns and processes of glass sponge reefs

Abstract

The glass sponge reefs of western Canada are modern analogues to ancient reefs and are unique habitats requiring conservation. However, the patterns and processes of the glass sponges have not been empirically studied. Here, I characterized the biology of the glass sponges in their reefs. I examined the community structure of the sponges at 3 reefs in the Strait of Georgia (SOG), their role in silica cycling, and the stable isotopes (δ13C and δ15N) of the reef forming sponge Aphrocallistes vastus. Sponges are spatially structured in patches which localize the abundance of other animals. Long term dissolution of spicules is negligible and thus a reef can be considered a silica sink. Lastly, isotope compositions can differentiate populations of A. vastus and depleted carbon signatures at 2 reefs suggest a terrestrial component in their diet. My work represents the biological baseline of 3 glass sponge reefs in the SOG.