The seas and oceans cover approximately 70% of the Earth’s surface forming its largest habitat and have a huge impact on our lives in general. All living things—from a bacterium to a giant redwood, a hummingbird to an elephant—trace their ancestry to an aquatic lifeform. Today, oceans, seas, rivers, lakes, and streams—a network that connects every corner of our world—are humanity's most important food source. And among other interactions, the oceans, seas, lakes, and rivers regulate gases in the atmosphere and play an important part in climate control.
The areas that divers generally venture into are the shallower regions that are near land. Climate and geological conditions influence these areas the most. For example, rivers bring fresh water, sediments, and pollution from our cities and towns. Natural erosion and human settlements change coastlines. Weather impacts conditions, waves break, and water movement creates currents. As a diver, you are entering this environment and must learn how it will affect you and how you will affect it. As a diver, you will become an advocate for the blue water planet. You should educate yourself further about the environment, and be aware of the need to protect and conserve it.
The following are the unit objectives:
- Describe the effects the environment has on diving
- Outline the differences between saltwater and freshwater diving
- Describe passive and active interactions with marine life
- Describe what a coral reef is and how important the reefs are to all life on earth
- List some general types of marine life