Coral Reefs and Oil Spills: A Guided Tour

One of nature's most spectacular creations, coral reefs are also among the most complex, diverse, and economically valuable ecosystems in the world. Sadly, coral reefs are being rapidly damaged from both natural and human causes. This tour will give you a basic overview of coral reefs, some of the threats they face, and some of the ways we can restore reefs that have been damaged.

Note:  This guided tour refers only to coral reefs found in shallow tropical waters.

Part 1: What are coral reefs?

Tiny individual coral polyps, related to sea anemones, create reefs by secreting limestone skeletons. Coral polyps divide as they grow and form coral colonies, creating a coral reef.

Each individual polyp harbors symbiotic algae, called zooxanthellae. Zooxanthellae use sunlight to make oxygen and food that the polyps use, and the polyps, in turn, produce wastes that the zooxanthellae need. Thus, coral reefs can only grow where water is clear enough to allow adequate light penetration for photosynthesis.

Not all corals build reefs, however. Soft corals, which include sea fans, sea plumes, and sea whips, are important components of coral communities.

Coral reefs provide food and shelter for many fish and invertebrates. For example, sea turtles shelter in reef overhangs and forage for sponges and other food items; manatees feed in reef-associated seagrass beds.