The glass fibers form a crown at its base that appear to help anchor the sponge to the ocean floor. The fibers are about 2 to 7 inches long and each is about the thickness of a human hair.
You can pick up a synthetic sponge for just a few dollars. But a natural sea sponge, hand-harvested from the Mediterranean seafloor, could set you back $30. Harvesting these sponges is dangerous ...
Beneath the ocean's surface, simple marine animals called sea sponges grow delicate glass skeletons that are as intricate as they are strong. These natural structures are made of a material called ...