"How inappropriate to call this planet Earth, when clearly it is Ocean." Arthur C. Clarke

For centuries, people have been challenged by the mysteries that lie beneath the blue depths of our ocean planet. Very little was known about the ocean until late in the nineteenth century. Myths and misconceptions abounded. We thought that the seafloor was flat and that it was the same age as the continents. How different a picture we now have of the ocean as the sea has begun to yield its secrets!

Today's scientists have overcome many of the challenges of the deep by using more sophisticated tools. They can send manned submersibles and sampling devices to plumb the ocean depths, taking photographs and samples of animal life and sediment to bring back to the surface for further study. Even space technology enters the picture.

" Why am I doing this? Only the tiny sea of my cells replies, reminding me that I am the sea and the sea is in me." Jacques-Yves Cousteau

The world ocean contains about 97 percent of all the water on the earth. Most of the remaining water is frozen in glaciers and icecaps. The rest is in lakes and rivers, underground, and in the air. Each of the oceans, Pacific, Atlantic, Indian, Arctic, makes a contribution to the entire global system and cover 71 percent of the earth's surface. The Pacific Ocean is the largest ocean by far covering about 70 million square miles (181 million square kilometers), nearly a third of the earth's surface. Also, the world ocean has an average depth of 12,200 feet (3,730 meters), but parts of the ocean plunge much deeper. The deepest areas occur in trenches, long narrow valleys on the sea floor. The deepest known spot is in the Mariana Trench in the western Pacific Ocean, near the island of Guam. It lies 36,198 feet (11,033 meters) below sea level. If the world's highest mountain, 29,035-foot (8,850-meter) Mount Everest, were placed in that spot, more than 1 mile (1.6 kms) of water would cover the mountaintop.

• The wealth of ocean

" Nor are the two bodies of flowing water alike,the one palatable, sweet, and pleasant to drink, and the other, salt and bitter.Yet from each (kind of water) do ye eat flesh fresh and tender, and ye extract ornaments to wear ;and thou seest the ships therein that plough the waves, that ye may seek (thus) of the bounty of God that ye may be grateful."
<Qur'an-Fatir 35:12>

Indeed God provides through the ocean many major resources. They include food, medicines, energy ,and minerals.

Food from the ocean consists mainly of fish and shellfish. The worldwide commercial fish and shellfish catch from the ocean totals about 200 billion pounds (90 billion kilograms) annually. Most of the catch comes from coastal waters. People eat about 60 percent of the fish and shellfish directly. Processors use the rest of the catch to make such products as fish oil and fish meal, which is added to livestock feed and pet food.

Medicines have been produced from many forms of marine life. For example, plantlike organisms called red algae provide an anticoagulant, a drug that keeps blood from clotting. A species of marine snail produces a substance that relaxes muscles. Sea life has also been valuable in medical research. The blood of horseshoe crabs contains a substance used to test for various infections. The substance can also be used to determine the purity of many drugs. Researchers study giant nerve cells from lobsters, squids, and marine worms to learn more about nerve functions in people.

Energy from the ocean has several forms. Petroleum and natural gas are the ocean's most valuable energy resources. Offshore wells tap deposits of oil and gas beneath the sea floor. In the late 1990's, offshore wells produced about 30 percent of the world's oil and gas. Scientists estimate that from 63 billion barrels to as much as 530 billion barrels of oil lie undiscovered beneath the ocean. Equally huge amounts of untapped gas accompany the oil. As gas and oil reserves on land are used up or become too difficult and expensive to obtain, finding and recovering undersea deposits will become increasingly important.
The ocean tides also provide energy. Tidal power facilities use the energy in the rise and fall of the tides to produce electricity. The first tidal power plant opened in 1966 on the Rance River near St.-Malo, France.

Minerals recovered from the ocean include sand and gravel mined from the sea floor and used to make construction materials. Some sands also have value because they are rich in phosphorite and other chemicals. Seawater itself contains such important minerals as bromide, manganese, and salt. The minerals can be removed by letting the seawater evaporate in large shallow basins under sunlight. The evaporation leaves the minerals behind. Other methods to remove minerals from seawater include chemical and electrochemical processes.
The mineral wealth of the ocean extends to the deep-sea floor. Deposits near undersea hot springs contain copper, iron, and zinc. Manganese deposits lie on the ocean bottom in lumps called nodules. The nodules also contain cobalt, copper, and nickel. Scientists are trying to develop ways to gather the nodules and bring them to the surface. Possible gathering techniques include using buckets that run on conveyor belts between a ship and the sea floor and operating a device that works like a giant vacuum cleaner.

Plate Tectonics