The world’s ocean is a vast reservoir of salt water that covers almost three fourths of Earth’s surface and makes life on the planet possible. It is a vital source of food for many living things and it contributes to the temperature, rainfall, and weather of the continents that surround it. The ocean is a dynamic, ever-changing, and important part of the global system of ecosystems that supports human life.
The word “ocean” is derived from the Greek word (ócein), meaning big sea, and it was originally used to describe all of the water on Earth. Today, however, the term is often used to refer specifically to a particular large body of salt water, such as the Atlantic Ocean, Pacific Ocean, or Arctic Ocean.
Oceans form when tectonic plates on the Earth’s surface move apart and separate molten rock from below. This process is called seafloor spreading, and it creates underwater mountain ranges known as mid-ocean ridges over long periods of time. Oceans then fill the spaces between them with a layer of salt water, called seawater. These waters are constantly moving, and they are influenced by a variety of forces such as winds and currents.
These movements are what cause waves. They can be gentle breezes that create ripples or powerful stormy weather that creates large swells. Ocean water is also affected by a force called gravity, which causes the rise and fall of sea levels. This is the phenomenon we see every day on beaches, when more sand is exposed at high tide than at low tide. Oceans are amazingly deep, with the Atlantic and Pacific Oceans reaching depths of more than 8,000 meters. The Mariana Trench, in the Pacific, is the deepest measured ocean location and can reach nearly 11,000 meters.
There are over 226,000 species of organisms that make the ocean their home. Scientists are still discovering new marine species, and they are concerned that some of these animals may be endangered by rising sea temperatures and pollution.
Ocean literacy is the ability to understand and value marine environments, and it is essential for healthy oceans. People who feel a strong connection to the ocean tend to protect it, and they are more likely to want to share knowledge about it with others. This is known as environmental stewardship.
While increasing urbanisation and coastal development are reducing people’s access to ocean environments, some marine-centred activities and educational initiatives can help to foster these connections and improve ocean literacy. In particular, experiential forms of learning such as surfing, diving, and sailing are important because they can help people develop a sense of place in the ocean that can be cultivated over time.
This is a developing field, and researchers are currently exploring how ocean-centred sports can foster a deeper understanding of marine environments and contribute to marine stewardship. In addition, they are exploring how ocean literacy can be developed and enhanced through the use of local and traditional knowledge.