Oceans of the World
The ocean surrounds the majority of parts of the earth. It is estimated that 71 per cent of the earth’s surface is covered with water. Approximately 361,000,000 km2 of the planet is covered by seawater. The ocean is a key component of the earth’s hydrosphere, making it imperative for life on earth. The ocean acts as a huge heat reservoir and influences climate and weather patterns, the carbon cycle, and the water cycle. Ocean temperatures depend on the amount of solar radiation reaching the ocean surface. Ocean water consists of large quantities of dissolved gases like oxygen, carbon dioxide, and nitrogen. This gas exchange occurs at the surface of the ocean and solubility depends on the temperature and salinity of the water. The ocean provides crucial services like climate regulation, trade and transport, and access to food and other resources. The ocean is also home to more than 230,000 species and scientists suggest that many marine species are yet to be discovered. The oceans are broadly classified into five- The Pacific Ocean, The Atlantic Ocean, The Indian Ocean, The Southern Ocean, and The Arctic Ocean. Now, let’s have a look at each of these oceans.
The Pacific Ocean:
The Pacific Ocean is the largest and deepest of all oceans. The pacific ocean got its name from the Portuguese explorer Fernão de Magalhães who organized the first circumnavigation of the earth. The pacific ocean is ten times bigger than the smallest ocean, the arctic ocean and is bigger than the landmass of all continents. It covers more than 30 per cent of the earth’s total surface and 46 per cent of the earth’s water surface. The pacific ocean extends from the arctic ocean in the north to the southern ocean in the south and is bounded by the continents of Asia and Oceania in the west and the Americas in the east. The average depth of the pacific ocean is 4,200 meters. The deepest location on earth, the Mariana Trench is situated in the pacific ocean and has a depth of 10,928 meters. The deepest point in the Southern Hemisphere, the Horizon Deep (10,823 meters) in the Tonga Trench is also situated in the pacific ocean. In the winter season, the northern half of the north pacific experiences high winds of over 55 kilometers per hour, usually blowing from the west. These winds have the capability to generate sustained seas of over 5 meters in North America and the western shores of Hawaii. In the eastern Equatorial Pacific, light winds are experienced throughout the year and swell propagation from both the North and South Pacific westerlies maintains wave height. Throughout the year, strong westerlies flow between 35° and 60° latitudes in the South Pacific.
The Atlantic Ocean:
The Atlantic Ocean is the second largest of all oceans and it has an area of about 106,460,000 km2. It covers approximately 20 per cent of the earth’s total surface and 29 per cent of the earth’s water surface. The Atlantic Ocean is located between the Americas and European/African continents. The Atlantic Ocean forms an “S” shape and extends longitudinally between Europe and Africa to the east and North and South America to the west. It is connected in the north to the Arctic Ocean, in the southwest to the Pacific Ocean, in the southeast to the Indian Ocean, and in the south to the Southern Ocean. The average depth of the Atlantic ocean is 3,660 meters and the deepest point in the ocean is situated in the Puerto Rico Trench (8,648 meters). The North Atlantic Ocean is a very rough ocean with strong winds of over 55 kilometers per hour. These strong winds generate a band of seas greater than 15 feet creating big waves to the eastern shore of the basin. On the other hand, the South Atlantic Ocean is the smallest ocean and has no tropical storms.
The Indian Ocean:
The Indian Ocean is the third largest of all oceans and it has an area of about 70,560,000 km2. The Indian Ocean is surrounded by Asia to the north, Africa to the west, and Australia to the east. The Indian Ocean also consists of seas like the Arabian Sea, the Laccadive Sea, the Bay of Bengal, and the Andaman Sea. The average depth of the Indian Ocean is 3,897 meters. The deepest point of the Indian Ocean is the Java Trench located at the south of Java in the eastern part of the Indian Ocean and it is having a depth of 7,725 meters. The Indian Ocean contains an additional 20 per cent of the water on Earth’s surface. The Indian Ocean is bounded by 4 tectonic plate boundaries and may include an additional plate boundary. It has a higher water temperature so that marine life is limited. The temperatures of the Indian Ocean depend on the location and on the ocean’s currents. The average temperature of the Indian Ocean is 22 degrees Celsius. In coastal regions near the equator, the temperature reaches 28 degrees Celsius and in southern regions near the polar regions, the temperature drops drastically below 40 degrees latitude south. The northern part of the Indian Ocean is an important trade and transport area for oil. The Indian Ocean connects each of the oil-rich countries of the Middle East with Asia. It is estimated that 40% of the world’s offshore oil production comes from the Indian Ocean mainly from the oilfields of Indonesia and the Persian Gulf.
The Southern Ocean:
The southern ocean is also known as the “Antarctic Ocean” and has a size of 20,327,000 km2. The southern ocean encircles the continent of Antarctica. The southern ocean has been subjected to rapid climatic changes over the past 30 years and as a result of this various changes have occurred in the marine ecosystem. Most people of Continental Europe and North America consider this area of the ocean as parts of the Pacific, Atlantic, and Indian Oceans. They actually do not even call a name for this ocean. But, for a long time, mariners call this ocean as the southern ocean and it is how the ocean got its name. The southern ocean was officially accepted as an ocean by International Hydrographic Organization in 2000. The southern ocean is predominantly deep water and has an average depth of 3,270 meters. The southern ocean is the least understood ocean among all the oceans. This is because the ocean is very far from populated areas and has a severe climate.
The Arctic Ocean:
The Arctic Ocean is the smallest and shallowest of all oceans and spans an area of approximately 14,060,000 km2. It is also the coldest ocean among the five oceans in the world. The International Hydrographic Organization (IHO) considers it as an ocean but still, some oceanographers call it the Arctic Mediterranean Sea. The Arctic Ocean is located at the North pole and is completely encircled by the landmasses of North America, Eurasia, and Greenland. The size of this ocean is 14,056,000 km2 and hence it is smaller than the largest country in the world, Russia. The average depth of the Arctic Ocean is 987 meters and the deepest point detected is 5,502 meters. The Arctic Ocean was covered by ice in the past, but the situation is changing nowadays as the glaciers are melting especially due to global warming. This affects the entire world as the sea levels are rising. Due to the excessively cold climate, marine life is very rare in the Arctic Ocean except in its southern parts.
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