Introduction to CORAL REEFS

Coral reefs are living, colorful, multi-faceted underwater ecosystems, a home to a diversity of fish, invertebrates, (crabs, shrimp, sea stars) algaes and more. They are underwater communities that never rest. As a snorkeler or a diver, you are immersed in this dynamic underwater world.

Coral reefs first appeared over 400 million years ago and the coral reefs as we now know of them, today appeared less than 25 million years ago.

Coral reefs are marine ecosystems that are colonies of living animals. These colonies are groups of individual animals called polyps. The polyps actually secrete a substance that is called calcium carbonate that forms the reef structure upon which they live.

Coral reefs live in a warm water ecosystem that has a temperature range of between 21 to 29 degrees Celsius or 70 to 85 degrees Fahrenheit. They need plenty of light in which to grow; and grow best in waters less than 23 meters or 75 feet in depth.

Light is essential to coral reef animals, especially in regards to photosynthesis. Within each coral polyp are single celled algae called zooxanthellae. Zooxanthellae, utilize sunlight for photosynthesis, a process by which the algae is using the sunlight to produce food and oxygen for the polyp. In return, the zooxanthellae receive compounds needed for sustenance and photosynthesis. Thus, the polyp and zooxanthellae live in a relationship that is mutually beneficial for both.

70 percent of our earth's surface is covered by oceans, yet less than .1% of the world's oceans surface is covered by coral reefs. If all the reefs were placed together, the equivalent area would be equal to half the size of France.

Do you know that 25 percent of all marine species of animals live on coral reefs? It has been estimated that at least 100,000 species from almost every phylum live on tropical coral reefs. (A phylum being - a primary division in the plant or animal kingdoms) 4000 species from 100 families of fish have been documented at this time and more species are yet to be discovered.

Coral reefs are important. Not only are they important in terms of worldwide tourism, but for other reasons as well.

Coral reefs serve as indicators of the health of our planet. They represent how effectively we are caring for our earth.

Importantly, they serve as protection for coastlines. In addition, they are an essential source of food and protein for millions of people throughout the world. No wonder 500 million people live within 60 miles of coral reefs! Coral reefs provide medical benefits to us as well. A chemotherapy drug used to treat leukemia is derived from sponges that live on the reefs. Antiviral drugs are also derived from sponges.

Conclusion: Coral reefs, the vibrant underwater communities that are often called the rainforests of the sea.

Built up over time, these oceanic colonies of animals impact the lives of other marine animals as well as our own.

Their beauty and complexity will entice us to explore them again and again... and, will invite us to care for them now, and for future generations.