The ocean world

The sea is the largest unknown part of the world. It covers 71 percent of the earth. But we know very little about it.

The first oceanographic voyage was made in 1872 when an English ship, the Challenger, sailed from England on a three-and-one-half-year journey through the world's oceans. From this voyage came information that formed the principles on which oceanographic studies were based for the next half century. In her travels, the Challenger sailed in every important part of the sea, except the arctic regions.

Six scientists on the ship conducted studies of the ocean conditions. They established 362 observing "stations" during their voyage. During a station, some of which lasted more than two days, the ship stopped while measurements and examples were taken. The information obtained included water temperature, conditions of the climate, direction, and speed of the surface and deep-water currents. Examples were collected of water and ocean bottom, and of animal and plant life, including 4717 kinds never before known. Although the instruments used by the Challenger were simple compared with today's, some very useful information was gathered during the voyage. Fifty large books were written about the Challenger.

Other voyages soon followed. One was made by Fridtjof Nansen and his brave men to the arctic in the small ship Fram. During the last part of the 19th century more studies and maps were made than ever before in the Pacific, the Indian Ocean and the Caribbean Sea.

The Climate "Machine". – The sea is a part of a great climate "machine" that cools and waters the earth when it needs it, warms the colder regions, and keeps the air we breathe fresh and pure.

Because water can hold 3 000 times more heat than air, the ocean has become the vast container for the earth's supply of heat energy, most of which comes from the sun. Although the air surrounding the earth is usually calm, the heat energy from the sun keeps it moving. Winds blow across the surface of the earth and spread this energy.

When the energy from the sun is taken in by the ocean, more mixing begins as currents carry it from one part of the sea to another. Here, too, the principle that heat will rise is proved as warm waters stay on the surface and colder waters go down.

On the top level of the ocean and on the land, steam from water returns to the air and rises in the heat to form rain clouds in the cool upper air. When the water in these clouds becomes heavy, it changes into rain. In very cold air the water stays together closely and forms snow.

Temperature. – Temperature is one of the three main qualities of sea water that varies considerably all through the world ocean. The other qualities are salinity and pressure.

The temperature of the sea changes only a little along our coast. But in some parts of the ocean the surface temperature can vary from 28 degrees Fahrenheit in the arctic regions, to 86 degrees F. in the hot climates of the world.

How can water remain at 28 degrees without freezing? The secret is that the water contains salt, which gives it a lower freezing point than the 32 degrees F. at which "pure" water freezes.

The Red Sea has the warmest water in the world – 90 degrees F. – almost hot to the touch. The Indian Ocean is also very warm with average temperatures of 80 degrees F. But 90 percent of the world ocean is cold, always below 40 degrees F. The ocean is deep, most of it two miles deep. Two miles is a long way from the surface sunshine.

Salinity. – Everyone knows that sea water is salty, but not many people know why. The reason is that salt and minerals are washed from the rocks on land and brought to the ocean by rivers, streams and rain.

After the three-and-a-half-year voyage of the Challenger it was discovered what most of these salts were. The total amount of salts in sea water varies in different parts of the ocean, depending on how warm the water is and how much surface water is changing into steam. The Red Sea which has the most salt, contains about 40 parts of salt to 1 000 parts of water. The arctic and antarctic waters are freshest, for very little of their water changes to steam. Also, water that is not salty is added from melting ice.

The most salty water is usually found near the surface. But recently an area of warm and salty water was discovered at the bottom of the Red Sea, 6 400 feet below the surface.

Scientists believe the ocean contains every known element, although only about 52 (including hydrogen and oxygen) have been discovered. The ocean even contains gold, silver, iron and tin.