First-Ever Submarine Dive on Vancouver's "Living Fossils": Glass Sponge Reefs

Researchers discover a seafloor oasis made of hundreds of glass sponges.

 

Howe Sound, British Columbia—Through the submersible's acrylic viewport, a large patch of glass sponges looms up from the seafloor of Howe Sound (map), a network of fjords located on Vancouver's doorstep. The sponges glow creamy white and orange under the sub's high-intensity lamps and extend across a 40-foot-high (12.2-meter-high) mound.

This week, the Canadian Parks and Wilderness Society (CPAWS) and Nuytco Research mounted the first submarine expedition to the glass sponge reefs found in Georgia Strait off of Vancouver.

The expedition aims to check on the status of these sponge reefs, which currently have no protection from damage by fishing activities, and to raise awareness of their existence.

The Howe Sound reef—which Aquarius will explore over the course of six dives—was first discovered in 2008, making it the most recently discovered sponge reef in southern British Columbia.
Glass sponges are found across the globe. But only along British Columbia's continental shelf do they grow over the skeletons of their dead ancestors to form massive deepwater reefs. This buildup is thanks to high levels of dissolved silica, which the sponges use to build their glass skeletons, and strong currents of cold water laden with nutrients.

"The sponge communities provide refuge for juvenile fish and they have a large filtering capacity, so they provide an important ecological function," says Bruce Reid, regional manager of Fisheries and Oceans Canada in Vancouver.

READ THE FULL STORY BY ANNE CASSELMAN HERE AT NATIONAL GEOGRAPHIC