OCeans :: essays research papers

Two-thirds of our planet is covered with oceans. The Pacific, the Atlantic, the Indian, and the Artic are the world's major oceans. They were formed by a series of geological processes that continue to affect the Earth. Seven main parts, called lithospheric plates, make up the Earth's mantle layer and crust. The plates fit together millions of years ago, and are constantly moving (at a slow pace-like a fingernail grows) over a layer of squishy, soft rock called asthenosphere that lies beneath the crust. Magma rises to fill the space when the two plates move away from each other to form an ocean. This is the way the ocean grows over millions of years. The ocean floor has an amazing landscape similar to dry land with huge mountains and deep valleys, slopes and plains, trenches and ridges. Through today's technology advances we are able to study the ocean deep and learn about it. The ocean is consistently moving. Its surface can change from calm and mirror like to wild and treacherous. Most waves at sea are caused by wind. The waves created the gales that blow during a tropical cyclone are 46ft and higher. The largest wave known to have been caused by the wind was 112ft high. Waves can also be created by volcanic eruptions. These waves are known at tsunamis. They are wide columns of water that reach down to the sea floor and can travel for great distances, at the speed of a jet plane. Colliding currents can also change the surface of the ocean. When the tide turns, the opposing currents meet and may create a whirlpool. Ocean currents are massive bodies of water that travel long distances around the world. Wind is the major force that creates currents. There are seven main ocean currents that move in large, circular streams at a walking pace. In the Northern Hemisphere currents move in a clockwise direction; in the Southern Hemisphere they are counterclockwise. Warm or cold water currents are carried by winds along the shorelines. This affects the climate of the various continents on the way. The current that carries warm water from the Caribbean Sea, up the east coast of the United Stated and then to the west coasts of Britain and Northern Europe is called the Gulf Stream. These areas would be much colder without the Gulf Stream. The "pull" of the moon and the sun also affect the ocean by causing the tides.