The role of seas and oceans


Ocean waters are in constant motion under the influence of solar heating, the Earth's rotation and gravity exerted by the sun and moon. The great ocean currents blend the warm waters of the tropics with the icy waters of the polar seas. This mix of warm and cold water plays a critical role in the earth's climate, the life-sustaining systems of oceans and the fishing stocks of the world.

The interaction of the atmosphere with the oceans and seas strongly influences climate and weather patterns. The oceans contribute to reducing the greenhouse effect by absorbing an enormous quantity of gases, especially CO₂.

Each year the oceans produce about 200 billion tonnes of floral plankton, mainly in coastal areas. Floral plankton is a group of organisms whose existence and development depends exclusively on solar energy and the presence of mineral salts and CO₂. It serves as a trophic basis for all sea creatures, feeding between 200 million and 400 million tonnes of fish per year.

Seawater and sea floors are both rich in minerals. One litre of seawater contains 29 grams of salt and one gram of magnesium. Potato-like lumps, called nodules, have been found on the ocean floor. They are extremely rich in minerals, such as magnesium, nickel and copper, which could be easily extracted. Saltwater can be distilled for drinking purposes.

For millennia man has used the sea for fishing, transport and trade. Today these uses continue, but other resources such as oil, gas and minerals are also extracted from coastal waters.

Sadly, our oceans have become a final dumping ground for humanity's waste, including sewage effluent, domestic refuse and nuclear by-products. All of these uses are beginning to have an effect on the marine environment.