Wild Reef Sand

Philippines sand is pulverized coral, and it can take several routes before it reaches the reef floor or beach. The coarsest sand, found on the reef floor, is coral rubble. Chunks of coral skeleton, made of calcium carbonate, are broken off the reef by crashing waves and tropical storms. Shedd shipped 17.5 tons of this coarse sand from the Philippines to create a natural seabed in the 400,000-gallon shark habitat in Wild Reef. Continued wave action erodes the coral, breaking it into ever-smaller pieces and grinding it smooth.

The finest sand, however, reaches the beach by way of parrotfish. They use their sharp beak-shaped teeth to scrape algae from coral skeletons as well as pluck polyps to get the zooxanthellae inside. In either process, they also munch and crunch the coral skeleton, which goes through the fish and exits as powdery sand. A single parrotfish produces about six pounds of sand a year.

Posted by Karen Furnweger, web editor