Jurassic Park Submerged
Building On The Dead
In the beginning, there was ice
Why B.C.? Scientists have an answer... and a nagging mystery.
The last Ice Age swept across British Columbia over 11,500 years ago. It froze the ocean. When the ice retreated, it scraped a trench in the ocean floor in Hecate Strait. Glass sponges migrated into this protected trench and started building their reefs onto large boulders.
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The sponges found an excellent location. They are made of silica – the building block of glass – thus, they are exceedingly fragile and need protection from turbulent currents. They also need cold water and particles of food floating by to feed their bodies.
B.C.'s continental shelf provides those things, but so do other spots in the northern hemisphere. And that's where the mystery comes in. Why B.C.?
The answer:
Scientists say it was the perfect mix of sediments and geology on the shelf that spurred the reef-building. B.C.'s coastal mountains are rich in silica – the substance sponges use to build their skeletons. (Silica streams into the ocean, when mountains are weathered.) In fact, other than the waters of Antarctica, no other ocean in the world has the rich concentration of dissolved silica.
The nagging mystery: Could sponge reefs exist elsewhere?
"It is highly unlikely," says Dr. Manfred Krautter, a German scientist considered the world expert on B.C.'s glass sponge reefs. "B.C. has unique marine conditions and these glass sponges have become quite finicky about where they build reefs. They've built a few other very small reefs in B.C. and Washington State. But we don't think reef-building of this magnitude exists anywhere else in the world. It's really very unlikely. The marine conditions just wouldn't be suitable."
More small reefs discovered in B.C.
To date, researchers have found several other very small glass sponge reefs along the B.C. coast, in addition to the four large ones in Hecate Strait. Two exist close to Vancouver.
Threatened!
Although B.C.'s glass sponge reefs have existed for 9,000 years, their future is by no means secure. Bottom trawling has already chewed up large parts of their delicate reefs and Canada is slow to protect them.
Why isn't Canada fully protecting these one-of-a-kind glass sponge reefs? That's the most perplexing mystery of all.
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