As a diver, you owe it to yourself to experience as many places to dive as possible. Many of you reading this text live near the ocean. Others are closer to fresh water. Many different environments are present in the oceans, mostly due to temperature variations. For divers, ocean coral reefs are the most fascinating. However, I wouldn’t diminish the joy diving in freshwater. The amount of life you will find present on a coral reef is beyond anything you can find above the surface. The closest comparison on the surface would be a rain forest. Like a rain forest, the coral reef is a unique community of life. On a coral reef, this life can be enjoyed snorkeling or on scuba. From the smallest phytoplankton (plants) and zooplankton (animals) that form the basis of the food chain, to the largest of the free-swimming fish and mammals, there is literally a world of life, all working together to form communities that build the largest animal-made structures on earth – the coral reefs. In this text you will learn how to both enjoy and help protect all these environments and creatures for our enjoyment, and perhaps survival, in the future. The health of our planet and all life is dependent on the health of the oceans. Half of the oxygen we breathe comes from the organisms that are present in the ocean.