Schauen Sie sich das kostenlose Video Dr. Manfred Krautter: Sponge Reefs an

Dr. Manfred Krautter, a paleobiologist, and professor at the University of Stuttgart, Germany, gives a talk on the rare Glass Sponge Reefs in the seas of British Columbia, off Canada's West Coast.
These glass sponge reefs were thought to be extinct and were only known by their fossil records, which Dr. Krautter and other scientists used for research studies.