Pacific Ocean is the largest ocean in the world. Covering almost one third of the earth’s surface area, Pacific Ocean has a total area of about 165.25 million square kilometres. Pacific Ocean corresponds to 46 percent of the earth’s water surface and is larger than all the land area on the earth combined together. The ocean is bounded by Americas in the east and Asia and Australia in the west. In the northern side, the ocean is connected to Arctic Ocean, and in the southern side, it is connected to the Antarctic Ocean. This large ocean was first sighted by the Europeans in the 16th century, and the name Pacific Ocean was given by Portuguese explorer Ferdinand Magellan in 1521 during the Spanish circumnavigation of the world.
The equator divides the ocean into northern Pacific Ocean and southern Pacific Ocean. The ocean is also where the deepest point on earth lies. The marina trench in the western north pacific is the deepest point on the world with a depth of 10911 meters.
Earth’s entire landmass takes up a total area of about, 150 million square kilometres. The largest ocean in the world, the Pacific Ocean itself has an area of more than 165.2 million square kilometres, thus making it the larger than anything else in the world. Pacific Ocean extends approximately 15500 kilometres from Bering Sea in the northern Arctic Ocean to Ross Sea in the southern Atlantic Ocean. The ocean also is more than 19800 kilometres wide between Indonesia in west to Columbia in the east. This distance is about halfway around the world and more than five times the diameter of the moon. The Pacific Ocean has a total water volume of 710,000,000 cubic kilometres and has an average depth of 4280 meters.
The size of Pacific Ocean is decreasing gradually, and the size of Antarctic Ocean is increasing because of the effect of plate tectonic movements. It is estimated that Pacific Ocean is shrinking by around 0.2 square kilometres year after year. Along the irregular western coasts of the Pacific Ocean, there are many small and large seas. The bigger ones among them are the Celebes Sea, Coral Sea, Sea of Japan, South China Sea, Tasman Sea, Sulu Sea, and yellow sea. The ocean is also connected to all other major oceans in the world. Pacific Ocean is connected to the Indian Ocean on its west through the Strait of Malacca. Pacific Ocean and Atlantic Ocean are connected through the Drake Passage and the Strait of Magellan. Pacific Ocean is also connected to the Arctic Ocean in the north through the Bering Strait.
As pacific lies across the 180th meridian, the western region of the pacific ocean which touches the shores of Asia lies in the eastern hemisphere; and the eastern region of the pacific ocean which touches the shores of America lies in the western hemisphere. Pacific Ocean got its name because, when Magellan crossed the Strait of Magellan to reach discover this ocean, he found the waters to be more peaceful. But in reality, Pacific Ocean is a very difficult place to survive. The islands in the Pacific Ocean are frequently affected by many tropical storms. The lands around the rim of this huge ocean are made of large number of active volcanoes, and are places often affected by strong earthquakes. And also underwater earthquakes in this ocean often lead to many tsunamis that devastate many islands and towns in the ocean.
Islands and surrounding landmasses
The islands in and around Pacific Ocean can be subdivided into three different groups known as Micronesia, Melanesia, and Polynesia. The islands which lies above the equator and west of the International Date Line comes under the group called Micronesia. This includes Mariana Islands, Caroline Islands, Marshall Islands and the islands of Kiribati which lies in the south west. The islands which lies in the south west region come under the group called Melanesia. This group includes the Bismarck Archipelago, Solomon Islands, Santa Cruz, Vanuatu, Fiji islands, and New Caledonia. The New Guinea, which is the largest island in the pacific and the second largest in the world after Greenland, also comes under this group of islands. The rest, and the largest group of islands, which stretches from Hawaii in the north to New Zealand in the south is called Polynesia. This group comprises of islands such as Tuvalu, Samoa, Tonga, Austral islands, Cook Islands, Marques islands, and Easter islands.
There are four different types of islands that we can see in Pacific Ocean. There are continental islands, high islands, coral reefs and uplifted coral platforms in Pacific Ocean. Continental islands are the islands that lie outside the andesitic line. These islands are generally large in size, and most of them are structurally associated with the nearby continents. The main continental islands include New Guinea, New Zealand, and Philippines.
High islands such as Hawaii and Solomon islands in pacific oceans are of volcanic origin. Most of the high islands also have active volcanoes. Coral reefs are mainly found in the South Pacific Ocean. These are low lying structures that have been made up on ballistic lava flows under ocean surface. The Great Barrier Reef off the north east coast of Australia is one among them. The uplifted coral platforms are islands which are slightly larger than the low lying coral islands. The islands of Banaba, Makatea, and Tuamotu islands come under this type.
Bordering countries and territories
Federated States of Micronesia
| Marshall Islands|
Papua New Guinea
| Solomon Islands|
| United States (Alaska, Washington, Oregon, California, Hawaii)
| American Samoa (USA)|
United States Baker Island (USA)
Cook Islands (New Zealand)
|Australia Coral Sea Islands (Australia)|
Easter Island (Chile)
French Polynesia (France)
| Guam (USA)|
Hong Kong (China)
United States Howland Island (USA)
United States Jarvis Island (USA)
|United States Johnston Island (USA)|
United States Kingman Reef (USA)
United States Midway Atoll (USA)
| New Caledonia (France)|
Niue (New Zealand)
Norfolk Island (Australia)
| Northern Mariana Islands (USA)|
United States Palmyra Atoll (USA)
Pitcairn Islands (UK)
Tokelau (New Zealand)
| Wallis and Futuna (France)
United States Wake Island (USA)
About 50.1 percent of the ocean water in the world is in Pacific Ocean. The Pacific Ocean has a volume of around 714 million cubic kilometres. The surface water temperatures in Pacific Ocean varies across the latitudes, with temperatures as high as 30⁰C near equatorial region, and up to -1.4⁰C near polar areas. Along with temperature, the salinity levels of the water also vary. The salinity levels are found highest in the tropical regions. The equatorial regions have salinity levels of up to 34 parts per thousand, which is lesser, compared to the tropical areas because of the abundant equatorial precipitation throughout the year. The salinity levels are lowest near the Polar Regions where the levels are around 32 parts per thousand.
The ocean currents in the Pacific Ocean are generally clockwise in the northern hemisphere and anti clockwise in the southern hemisphere. The trade winds drive the equatorial currents of north westward along the 15⁰N latitude. These currents turns north near the Philippines to become the arm kuroshio currents which flow past Japan. This kuroshio currents turn eastwards at about 45⁰ N latitude and becomes Aleutian currents which moves towards America and then flows south as the California current thus completing the circulation in the northern hemisphere.
The equatorial currents in the southern hemisphere which moves westward because of the influence of the trade winds, turns southwards near New Guinea. This southward flowing current turns eastward as it reaches 50⁰ south latitude where it meets with the Antarctic circumpolar currents. This current when reaches Chilean coast, divides into two; one flowing around the cape horn, and the other flowing northward to form the Humbolt current which completes the circulation in the southern hemisphere.
The southern Pacific and eastern Pacific have trade winds that are remarkably steady. In contrast, the conditions in the North are found to be varied. For example, the east coast of Russia has got cold winter temperatures, whereas the coast of British Columbia has a milder weather in the winter months.
The El Nino Southern Oscillation affects the weather conditions in the tropical and sub-tropical regions. In the tropical western Pacific, dry winds blow in the winter seasons, whereas the season is wet during the summers. By late summer, tropical cyclone activity is at its peak due to the temperature difference between the sea and land.
The icing from October to May in the arctic region causes hazards for shipping. From June to December, persistent fog is found to occur. In the Gulf of Alaska, there is a climatological low which keeps the climate mild and wet in the winter. The temperature difference between Antarctica and the tropics causes the Westerlies and the Jet stream within the mi-latitudes to get particularly strong.
Petroleum and natural gas can be extracted from the shallow waters of the continental shelves that lie off the coasts of New Zealand and Australia. Along the coasts of the countries of Japan, Australia, Nicaragua, Panama, Papua New Guinea, and the Philippines, pearls are harvested.
In the Pacific, fish are seen as an important economic asset. Herring, sardines, swordfish, salmon, snapper, shellfish, and tuna are found in the shallower waters of the continents and also the more temperate islands. Overfishing has turned out to be a big issue in some areas.