The Five Oceans
- Earth is mostly water. Three-quarters of this planet is covered by water bodies, with the biggests ones being the five oceans (the Atlantic, Pacific, Southern, Indian, and Arctic oceans).
- Ninety four percent of all life forms on Earth are aquatic. From this number, ninety percent resides in the ocean’s “abyssal zone.”
- Humans have documented space and other planets better than they have mapped the ocean floor. It is estimated that only about five percent of the world’s oceans have been totally explored.
- Oceans have an average depth of two and a half miles (13200 ft).
- The ocean is three percent salt. Its salinity is estimated to be around 34 to 36 ppt (parts per thousand), whereas fresh water has a salinity of 0 ppt.
- Light can’t penetrate 300 feet through the ocean; this area that can never be touched by sunlight is called the “deep sea.”
- There is gold in the water! It is estimated that the world’s oceans and seas contain about twenty million tons of this precious metal.
- Marine biologists estimate that only two-thirds of marine life have been documented and studied. There are millions more species that remain to be discovered.
- “Rivers” and deep “lakes” can exist under the ocean. This can happen when salty water and hydrogen sulfide mix to form a dense brine that is heavier than regular seawater.
- There are kelp forests under the ocean that can rival even the lushest of forests on land. Kelp can grow up to two feet PER DAY, so these forests can grow on the ocean floor a hundred fifty feet deep, and reach the surface of the water.
Depth of the Ocean
List 5 things you know about the ocean based on this infographic.
The Deepest Part of the Ocean: the Mariana Trench
The Mariana Trench is the deepest part of the Earth’s ocean and is also the lowest point on the Earth’s crust. It is estimated to be 10,971 meters (35,994 feet) deep and is located in the western Pacific Ocean.
Pulleys and Gears in an Ocean Habitat