Coral reefs are massive structures made of limestone deposited by coral polyps

Often referred to as the “rainforests of the sea,” coral reefs support approximately 25 percent of all known marine species. Reefs provide homes for more than 4,000 species of fish, 700 species of coral, and thousands of other plants and animals.

The architects of coral reefs are hard corals. Unlike soft corals, hard corals have stony skeletons made out of limestone that is produced by coral polyps. When polyps die, their skeletons are left behind and used as foundations for new polyps. An actual coral branch or mound is composed of layer upon layer of skeletons covered by a thin layer of living polyps.

If a coral reef is likened to a bustling city, then a coral colony is like a single apartment building with many rooms and hallways that house different marine species.

The Florida Keys are home to North America's only coral barrier reef. The Florida reef tract extends from Soldier Key located in Biscayne Bay to the Tortugas Banks. The tract stretches for nearly 150 miles in length and is about four miles wide.