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88-545: The Nukumanu Islands , formerly the Tasman Islands , is an atoll of Papua New Guinea , located in the south-western Pacific Ocean , 4 degrees south of the Equator . Comprising a ring of more than twenty islets on a reef surrounding a large lagoon, Nukumanu's sandy islands are located on a strip of coral rising no more than 1 metre (3.3 ft) above sea level. The main inhabited islands of Nukumanu are located on

176-508: A reef knoll refers to the elevated remains of an ancient atoll within a limestone region, appearing as a hill. The second largest atoll by dry land area is Aldabra , with 155 km (60 sq mi). Huvadhu Atoll , situated in the southern region of the Maldives, holds the distinction of being the largest atoll based on the sheer number of islands it comprises, with a total of 255 individual islands. In 1842, Charles Darwin explained

264-648: A central lagoon . Important human migrations occurred in the Pacific in prehistoric times. Modern humans first reached the western Pacific in the Paleolithic , at around 60,000 to 70,000 years ago. Originating from a southern coastal human migration out of Africa, they reached East Asia , Mainland Southeast Asia , the Philippines, New Guinea , and then Australia by making the sea crossing of at least 80 kilometres (50 mi) between Sundaland and Sahul . It

352-664: A lagoon in which there are no promontories other than reefs and islets composed of reef detritus " or "in an exclusively morphological sense, [as] a ring-shaped ribbon reef enclosing a lagoon". There are approximately 440 atolls in the world. Most of the world's atolls are in the Pacific Ocean (with concentrations in the Caroline Islands , the Coral Sea Islands , the Marshall Islands ,

440-525: A volcanic island in the tropical sea will grow upward as the island subsides (sinks), becoming an "almost atoll", or barrier reef island, as typified by an island such as Aitutaki in the Cook Islands, and Bora Bora and others in the Society Islands. The fringing reef becomes a barrier reef for the reason that the outer part of the reef maintains itself near sea level through biotic growth, while

528-479: Is 4,280 m (14,040 ft; 2,340 fathoms), putting the total water volume at roughly 710,000,000 km (170,000,000 cu mi). Due to the effects of plate tectonics , the Pacific Ocean is currently shrinking by roughly 2.5 cm (1 in) per year on three sides, roughly averaging 0.52 km (0.20 sq mi) a year. By contrast, the Atlantic Ocean is increasing in size. Along

616-487: Is an Indo-Aryan language spoken in the Maldives . The word's first recorded English use was in 1625 as atollon . Charles Darwin coined the term in his monograph, The Structure and Distribution of Coral Reefs . He recognized the word's indigenous origin and defined it as a "circular group of coral islets", synonymously with "lagoon-island". More modern definitions of atoll describe them as "annular reefs enclosing

704-491: Is not known with any certainty what level of maritime technology was used by these groups – the presumption is that they used large bamboo rafts which may have been equipped with some sort of sail. The reduction in favourable winds for a crossing to Sahul after 58,000 B.P. fits with the dating of the settlement of Australia, with no later migrations in the prehistoric period. The seafaring abilities of pre-Austronesian residents of Island South-east Asia are confirmed by

792-573: Is the largest raised coral atoll of the world, followed by Rennell Island (660 km , 250 sq mi). More sources, however, list Kiritimati as the largest atoll in the world in terms of land area. It is also a raised coral atoll (321 km , 124 sq mi land area; according to other sources even 575 km , 222 sq mi), 160 km (62 sq mi) main lagoon, 168 km (65 sq mi) other lagoons (according to other sources 319 km , 123 sq mi total lagoon size). The geological formation known as

880-697: The Americas , although evidence for this remains inconclusive. The first contact of European navigators with the western edge of the Pacific Ocean was made by the Portuguese expeditions of António de Abreu and Francisco Serrão , via the Lesser Sunda Islands , to the Maluku Islands , in 1512, and with Jorge Álvares 's expedition to southern China in 1513, both ordered by Afonso de Albuquerque from Malacca . The eastern side of

968-424: The Americas , more than 25,000 islands, large and small, rise above the surface of the Pacific Ocean. Multiple islands were the shells of former active volcanoes that have lain dormant for thousands of years. Close to the equator, without vast areas of blue ocean, are a dot of atolls that have over intervals of time been formed by seamounts as a result of tiny coral islands strung in a ring within surroundings of

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1056-639: The Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica ) in the south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east. At 165,250,000 square kilometers (63,800,000 square miles) in area (as defined with a southern Antarctic border), this largest division of the World Ocean and the hydrosphere covers about 46% of Earth's water surface and about 32% of

1144-520: The Bering Sea in the Arctic to the northern extent of the circumpolar Southern Ocean at 60°S (older definitions extend it to Antarctica 's Ross Sea ), the Pacific reaches its greatest east–west width at about 5°N latitude , where it stretches approximately 19,800 km (12,300 mi) from Indonesia to the coast of Colombia  – halfway around the world, and more than five times

1232-599: The Colombian department of San Andres and Providencia in the Caribbean. Reef-building corals will thrive only in warm tropical and subtropical waters of oceans and seas, and therefore atolls are found only in the tropics and subtropics. The northernmost atoll in the world is Kure Atoll at 28°25′ N, along with other atolls of the Northwestern Hawaiian Islands . The southernmost atolls in

1320-565: The German colonial empire . It was captured by Australia in 1914 and formally transferred to Australian administration as a League of Nations mandate in 1920 by the Treaty of Versailles , after Germany's defeat in World War I . Nukumanu's most recent claim to fame is that it was the last place on the path of Amelia Earhart before she and her co-pilot Fred Noonan disappeared forever into

1408-976: The North Pacific Ocean and the South Pacific Ocean (or more loosely the South Seas ). The Pacific Ocean can also be informally divided by the International Date Line into the East Pacific and the West Pacific , which allows it to be further divided into four quadrants, namely the Northeast Pacific off the coasts of North America , the Southeast Pacific off South America , Northwest Pacific off Far Eastern / Pacific Asia , and

1496-601: The Pacific War ; however, by the end of that war, Japan was defeated and the U.S. Pacific Fleet was the virtual master of the ocean. The Japanese-ruled Northern Mariana Islands came under the control of the United States. Since the end of World War II, many former colonies in the Pacific have become independent states . The Pacific separates Asia and Australia from the Americas. It may be further subdivided by

1584-551: The Royal Society of London carried out drilling on Funafuti atoll in Tuvalu for the purpose of investigating the formation of coral reefs . They wanted to determine whether traces of shallow water organisms could be found at depth in the coral of Pacific atolls. This investigation followed the work on the structure and distribution of coral reefs conducted by Charles Darwin in the Pacific. The first expedition in 1896

1672-738: The Sirena Deep , is also located in the Mariana Trench. The western Pacific has many major marginal seas , including the Philippine Sea , South China Sea , East China Sea , Sea of Japan , Sea of Okhotsk , Bering Sea , Gulf of Alaska , Gulf of California , Mar de Grau , Tasman Sea , and the Coral Sea . In the early 16th century , Spanish explorer Vasco Núñez de Balboa crossed the Isthmus of Panama in 1513 and sighted

1760-488: The Solomon Islands runs between these neighboring atolls, which form a small geographic group together with the wholly submerged Roncador Reef at the southern end. In Polynesian history, the main cultural and commercial exchanges took place with the inhabitants of neighboring Ontong Java Atoll, with whom Nukumanu people share many cultural affinities. Towards the end of the 19th century Nukumanu became part of

1848-725: The Southern Hemisphere . The North Equatorial Current , driven westward along latitude 15°N by the trade winds , turns north near the Philippines to become the warm Japan or Kuroshio Current . Turning eastward at about 45°N , the Kuroshio forks and some water moves northward as the Aleutian Current , while the rest turns southward to rejoin the North Equatorial Current. The Aleutian Current branches as it approaches North America and forms

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1936-710: The Southwest Pacific around Oceania . The Pacific Ocean's mean depth is 4,000 meters (13,000 feet). Challenger Deep in the Mariana Trench , located in the northwestern Pacific, is the deepest known point in the world, reaching a depth of 10,928 meters (35,853 feet). The Pacific also contains the deepest point in the Southern Hemisphere , the Horizon Deep in the Tonga Trench , at 10,823 meters (35,509 feet). The third deepest point on Earth,

2024-685: The Strait of Magellan to the Philippines , the explorer indeed found the ocean peaceful; however, the Pacific is not always peaceful. Many tropical storms batter the islands of the Pacific. The lands around the Pacific Rim are full of volcanoes and often affected by earthquakes . Tsunamis , caused by underwater earthquakes, have devastated many islands and in some cases destroyed entire towns. The Martin Waldseemüller map of 1507

2112-871: The Tuamotu Islands , Kiribati , Tokelau , and Tuvalu ) and the Indian Ocean (the Chagos Archipelago , Lakshadweep , the atolls of the Maldives , and the Outer Islands of Seychelles ). In addition, Indonesia also has several atolls spread across the archipelago, such as in the Thousand Islands , Taka Bonerate Islands , and atolls in the Raja Ampat Islands . The Atlantic Ocean has no large groups of atolls, other than eight atolls east of Nicaragua that belong to

2200-818: The Western Hemisphere . The Southern Pacific Ocean harbors the Southeast Indian Ridge crossing from south of Australia turning into the Pacific-Antarctic Ridge (north of the South Pole ) and merges with another ridge (south of South America) to form the East Pacific Rise which also connects with another ridge (south of North America) which overlooks the Juan de Fuca Ridge . For most of Magellan's voyage from

2288-583: The crab claw sail ) – it is likely that the progressive development of these technologies were related to the later steps of settlement into Near and Remote Oceania. Starting at around 2200 BCE, Austronesians sailed southwards to settle the Philippines . From, probably, the Bismarck Archipelago they crossed the western Pacific to reach the Marianas Islands by 1500 BCE, as well as Palau and Yap by 1000 BCE. They were

2376-602: The "northernmost atoll" at a latitude of 32°18′ N. At this latitude, coral reefs would not develop without the warming waters of the Gulf Stream . However, Bermuda is termed a pseudo-atoll because its general form, while resembling that of an atoll, has a very different origin of formation. In most cases, the land area of an atoll is very small in comparison to the total area. Atoll islands are low lying, with their elevations less than 5 metres (16 ft). Measured by total area, Lifou (1,146 km , 442 sq mi)

2464-908: The Atlantic, the Strait of Magellan was at times patrolled by fleets sent to prevent the entrance of non-Spanish ships. On the western side of the Pacific Ocean the Dutch threatened the Spanish Philippines . The 18th century marked the beginning of major exploration by the Russians in Alaska and the Aleutian Islands , such as the First Kamchatka expedition and the Great Northern Expedition , led by

2552-533: The Atlantic. The andesite line is the most significant regional distinction in the Pacific. A petrologic boundary, it separates the deeper, mafic igneous rock of the Central Pacific Basin from the partially submerged continental areas of felsic igneous rock on its margins. The andesite line follows the western edge of the islands off California and passes south of the Aleutian arc , along

2640-735: The Chilean coast, the South Equatorial Current divides; one branch flows around Cape Horn and the other turns north to form the Peru or Humboldt Current . The climate patterns of the Northern and Southern Hemispheres generally mirror each other. The trade winds in the southern and eastern Pacific are remarkably steady while conditions in the North Pacific are far more varied with, for example, cold winter temperatures on

2728-844: The Danish-born Russian navy officer Vitus Bering . Spain also sent expeditions to the Pacific Northwest , reaching Vancouver Island in southern Canada, and Alaska. The French explored and colonized Polynesia , and the British made three voyages with James Cook to the South Pacific and Australia, Hawaii , and the North American Pacific Northwest . In 1768, Pierre-Antoine Véron , a young astronomer accompanying Louis Antoine de Bougainville on his voyage of exploration, established

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2816-655: The Melanesian Archipelago of Papua New Guinea and the Solomon Islands respectively. The first serious research on Nukumanu's inhabitants was conducted by German ethnographers Ernst Sarfert and Hans Damm , during a German scientific expedition of the Southern Seas that took place in 1908–1910. This expedition visited both Nukumanu and neighboring Ontong Java Atoll, where they also carried out their research. Their work, "Luangiua und Nukumanu"

2904-613: The Moluccas, between 1525 and 1527, Portuguese expeditions encountered the Caroline Islands , the Aru Islands , and Papua New Guinea . In 1542–43 the Portuguese also reached Japan. In 1564, five Spanish ships carrying 379 soldiers crossed the ocean from Mexico led by Miguel López de Legazpi , and colonized the Philippines and Mariana Islands . For the remainder of the 16th century, Spain maintained military and mercantile control, with ships sailing from Mexico and Peru across

2992-429: The Pacific Ocean to the Philippines via Guam , and establishing the Spanish East Indies . The Manila galleons operated for two and a half centuries, linking Manila and Acapulco , in one of the longest trade routes in history. Spanish expeditions also arrived at Tuvalu , the Marquesas , the Cook Islands , the Solomon Islands , Vanuatu , the Marshalls and the Admiralty Islands in the South Pacific. Later, in

3080-399: The Pacific Ocean's irregular western margins lie many seas, the largest of which are the Celebes Sea , Coral Sea , East China Sea (East Sea), Philippine Sea , Sea of Japan , South China Sea (South Sea), Sulu Sea , Tasman Sea , and Yellow Sea (West Sea of Korea). The Indonesian Seaway (including the Strait of Malacca and Torres Strait ) joins the Pacific and the Indian Ocean to

3168-402: The Pacific in recorded history. They were part of a Spanish expedition to the Spice Islands that would eventually result in the first world circumnavigation . Magellan called the ocean Pacífico (or "Pacific" meaning, "peaceful") because, after sailing through the stormy seas off Cape Horn , the expedition found calm waters. The ocean was often called the Sea of Magellan in his honor until

3256-540: The Philippines already in 7000 BCE. Additional earlier migrations into Insular Southeast Asia, associated with Austroasiatic-speakers from Mainland Southeast Asia, are estimated to have taken place already in 15000 BCE. At around 1300 to 1200 BCE, a branch of the Austronesian migrations known as the Lapita culture reached the Bismarck Archipelago , the Solomon Islands , Vanuatu , Fiji , and New Caledonia . From there, they settled Tonga and Samoa by 900 to 800 BCE. Some also back-migrated northwards in 200 BCE to settle

3344-528: The United States. Significant contributions to oceanographic knowledge were made by the voyages of HMS Beagle in the 1830s, with Charles Darwin aboard; HMS Challenger during the 1870s; the USS Tuscarora (1873–76); and the German Gazelle (1874–76). In Oceania, France obtained a leading position as imperial power after making Tahiti and New Caledonia protectorates in 1842 and 1853, respectively. After navy visits to Easter Island in 1875 and 1887, Chilean navy officer Policarpo Toro negotiated

3432-416: The andesite line and include New Guinea, the islands of New Zealand, and the Philippines. Some of these islands are structurally associated with nearby continents. High islands are of volcanic origin, and many contain active volcanoes. Among these are Bougainville , Hawaii, and the Solomon Islands. The coral reefs of the South Pacific are low-lying structures that have built up on basaltic lava flows under

3520-408: The andesite line. Within the closed loop of the andesite line are most of the deep troughs, submerged volcanic mountains, and oceanic volcanic islands that characterize the Pacific basin. Here basaltic lavas gently flow out of rifts to build huge dome-shaped volcanic mountains whose eroded summits form island arcs, chains, and clusters. Outside the andesite line, volcanism is of the explosive type, and

3608-465: The antecedent karst model as they found that the morphology of modern atolls are independent of any influence of an underlying submerged and buried island and are not rooted to an initial fringing reef/barrier reef attached to a slowly subsiding volcanic edifice. In fact, the Neogene reefs underlying the studied modern atolls overlie and completely bury the subsided island are all non-atoll, flat-topped reefs. In fact, they found that atolls did not form doing

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3696-409: The approximately 440 atolls in the world are in the Pacific Ocean . Two different, well-cited models, the subsidence model and the antecedent karst model, have been used to explain the development of atolls. According to Charles Darwin 's subsidence model, the formation of an atoll is explained by the sinking of a volcanic island around which a coral fringing reef has formed. Over geologic time,

3784-409: The arctic, icing from October to May can present a hazard for shipping while persistent fog occurs from June to December. A climatological low in the Gulf of Alaska keeps the southern coast wet and mild during the winter months. The Westerlies and associated jet stream within the Mid-Latitudes can be particularly strong, especially in the Southern Hemisphere, due to the temperature difference between

3872-402: The atoll to persist, the coral reef must be maintained at the sea surface, with coral growth matching any relative change in sea level (sinking of the island or rising oceans). An alternative model for the origin of atolls is called the antecedent karst model. In the antecedent karst model, the first step in the formation of an atoll is the development of a flat top, mound-like coral reef during

3960-421: The base of a counter-clockwise circulation in the Bering Sea . Its southern arm becomes the chilled slow, south-flowing California Current . The South Equatorial Current , flowing west along the equator, swings southward east of New Guinea , turns east at about 50°S , and joins the main westerly circulation of the South Pacific, which includes the Earth-circling Antarctic Circumpolar Current . As it approaches

4048-417: The creation of coral atolls in the southern Pacific Ocean based upon observations made during a five-year voyage aboard HMS Beagle from 1831 to 1836. Darwin's explanation suggests that several tropical island types: from high volcanic island, through barrier reef island, to atoll, represented a sequence of gradual subsidence of what started as an oceanic volcano. He reasoned that a fringing coral reef surrounding

4136-408: The diameter of the Moon. Its geographic center is in eastern Kiribati south of Kiritimati , just west from Starbuck Island at 4°58′S 158°45′W  /  4.97°S 158.75°W  / -4.97; -158.75 . The lowest known point on Earth – the Mariana Trench  – lies 10,911 m (35,797  ft ; 5,966 fathoms ) below sea level. Its average depth

4224-402: The difference between temperatures aloft and sea surface temperatures is the greatest; however, each particular basin has its own seasonal patterns. On a worldwide scale, May is the least active month, while September is the most active month. November is the only month in which all the tropical cyclone basins are active. The Pacific hosts the two most active tropical cyclone basins , which are

4312-436: The direct result of the interaction between subsidence and preferential karst dissolution that occurred in the interior of flat topped coral reefs during exposure during glacial lowstands of sea level. The elevated rims along an island created by this preferential karst dissolution become the sites of coral growth and islands of atolls when flooded during interglacial highstands. The research of A. W. Droxler and others supports

4400-561: The dolomitization of calcite and aragonite within them. They are the evaporative, seepage-reflux, mixing-zone, burial, and seawater models. Although the origin of replacement dolomites remains problematic and controversial, it is generally accepted that seawater was the source of magnesium for dolomitization and the fluid in which calcite was dolomitized to form the dolomites found within atolls. Various processes have been invoked to drive large amounts of seawater through an atoll in order for dolomitization to occur. In 1896, 1897 and 1898,

4488-434: The east and the islands of Kiribati in the southeast. Melanesia, to the southwest, includes New Guinea , the world's second largest island after Greenland and by far the largest of the Pacific islands. The other main Melanesian groups from north to south are the Bismarck Archipelago , the Solomon Islands , Santa Cruz , Vanuatu , Fiji and New Caledonia . The largest area, Polynesia , stretching from Hawaii in

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4576-423: The east coast of Russia contrasting with the milder weather off British Columbia during the winter months due to the preferred flow of ocean currents . In the tropical and subtropical Pacific, the El Niño Southern Oscillation (ENSO) affects weather conditions. To determine the phase of ENSO, the most recent three-month sea surface temperature average for the area approximately 3,000 km (1,900 mi) to

4664-403: The eastern edge of the Kamchatka Peninsula , the Kuril Islands , Japan, the Mariana Islands , the Solomon Islands , and New Zealand's North Island . The dissimilarity continues northeastward along the western edge of the Andes Cordillera along South America to Mexico, returning then to the islands off California. Indonesia, the Philippines, Japan, New Guinea, and New Zealand lie outside

4752-442: The eastern end of the atoll. Administratively Nukumanu is part of the Autonomous Region of Bougainville in Papua New Guinea , but it lies quite far away from the closest territory of Papua New Guinea proper, which is the coast of New Ireland island at 682 km (424 mi) to the west. The nearest land is Ontong Java Atoll , located only 38 km (24 mi) to the south of Nukumanu. The border between Papua New Guinea and

4840-410: The eighteenth century. Magellan stopped at one uninhabited Pacific island before stopping at Guam in March 1521. Although Magellan himself died in the Philippines in 1521, Spanish navigator Juan Sebastián Elcano led the remains of the expedition back to Spain across the Indian Ocean and round the Cape of Good Hope , completing the first world circumnavigation in 1522. Sailing around and east of

4928-487: The equator into northern (North Pacific) and southern (South Pacific) portions. It extends from the Antarctic region in the South to the Arctic in the north. The Pacific Ocean encompasses approximately one-third of the Earth's surface, having an area of 165,200,000 km (63,800,000 sq mi) – larger than Earth's entire landmass combined, 150,000,000 km (58,000,000 sq mi). Extending approximately 15,500 km (9,600 mi) from

5016-469: The equator, which can have a salinity as low as 34 parts per thousand, is less salty than that found in the mid-latitudes because of abundant equatorial precipitation throughout the year. The lowest counts of less than 32 parts per thousand are found in the far north as less evaporation of seawater takes place in these frigid areas. The motion of Pacific waters is generally clockwise in the Northern Hemisphere (the North Pacific gyre ) and counter-clockwise in

5104-420: The first completely documented European landing in Australia (1606), in Cape York Peninsula , and Abel Janszoon Tasman circumnavigated and landed on parts of the Australian continental coast and arrived at Tasmania and New Zealand in 1642. In the 16th and 17th centuries, Spain considered the Pacific Ocean a mare clausum  – a sea closed to other naval powers. As the only known entrance from

5192-420: The first humans to reach Remote Oceania , and the first to cross vast distances of open water. They also continued spreading southwards and settling the rest of Maritime Southeast Asia , reaching Indonesia and Malaysia by 1500 BCE, and further west to Madagascar and the Comoros in the Indian Ocean by around 500 CE. More recently, it is suggested that Austronesians expanded already earlier, arriving in

5280-423: The great "Southern Sea" which he named Mar del Sur (in Spanish). Afterwards, the ocean's current name was coined by Portuguese explorer Ferdinand Magellan during the Spanish circumnavigation of the world in 1521, as he encountered favorable winds on reaching the ocean. He called it Mar Pacífico , which in Portuguese means 'peaceful sea'. Top large seas: Across the continents of Asia, Australia and

5368-439: The incorporation of the island into Chile with native Rapanui in 1888. By occupying Easter Island, Chile joined the imperial nations. By 1900 nearly all Pacific islands were in control of Britain, France, United States, Germany, Japan, and Chile. Although the United States gained control of Guam and the Philippines from Spain in 1898, Japan controlled most of the western Pacific by 1914 and occupied many other islands during

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5456-472: The inner part of the reef falls behind, becoming a lagoon because conditions are less favorable for the coral and calcareous algae responsible for most reef growth. In time, subsidence carries the old volcano below the ocean surface and the barrier reef remains. At this point, the island has become an atoll. As formulated by J. E. Hoffmeister, F. S. McNeil, E. G. Prudy, and others, the antecedent karst model argues that atolls are Pleistocene features that are

5544-417: The islands in the world. There are about 25,000 islands in the Pacific Ocean. The islands entirely within the Pacific Ocean can be divided into three main groups known as Micronesia , Melanesia and Polynesia . Micronesia, which lies north of the equator and west of the International Date Line , includes the Mariana Islands in the northwest, the Caroline Islands in the center, the Marshall Islands to

5632-519: The islands of eastern Micronesia (including the Carolines , the Marshall Islands , and Kiribati ), mixing with earlier Austronesian migrations in the region. This remained the furthest extent of the Austronesian expansion into Polynesia until around 700 CE when there was another surge of island exploration. They reached the Cook Islands , Tahiti , and the Marquesas by 700 CE; Hawaiʻi by 900 CE; Rapa Nui by 1000 CE; and finally New Zealand by 1200 CE. Austronesians may have also reached as far as

5720-446: The lagoon. This is exported mainly to Asia, and along with trochus shells, used to make mother-of-pearl, they comprise the backbone of the Nukumanu economy. This atoll has a Polynesian population whose ancestors migrated westwards out of Polynesia. Their language is classified in the Samoic–Outlier branch of Polynesian. The Nukumanu Islands, together with neighboring Ontong Java retain a Polynesian character despite their location in

5808-468: The north to New Zealand in the south, also encompasses Tuvalu , Tokelau , Samoa , Tonga and the Kermadec Islands to the west, the Cook Islands , Society Islands and Austral Islands in the center, and the Marquesas Islands , Tuamotu , Mangareva Islands , and Easter Island to the east. Islands in the Pacific Ocean are of four basic types: continental islands, high islands, coral reefs and uplifted coral platforms. Continental islands lie outside

5896-485: The northern Philippines , but also earlier groups associated with Austroasiatic-speakers , resulting in the modern peoples of Island Southeast Asia and Oceania. A later seaborne migration is the Neolithic Austronesian expansion of the Austronesian peoples . Austronesians originated from the island of Taiwan c.  3000 –1500 BCE. They are associated with distinctive maritime sailing technologies (notably outrigger boats , catamarans , lashed-lug boats, and

5984-433: The northwestern Pacific and the eastern Pacific. Pacific hurricanes form south of Mexico, sometimes striking the western Mexican coast and occasionally the Southwestern United States between June and October, while typhoons forming in the northwestern Pacific moving into southeast and east Asia from May to December. Tropical cyclones also form in the South Pacific basin , where they occasionally impact island nations. In

6072-399: The ocean was encountered by Spanish explorer Vasco Núñez de Balboa in 1513 after his expedition crossed the Isthmus of Panama and reached a new ocean. He named it Mar del Sur ("Sea of the South" or "South Sea" ) because the ocean was to the south of the coast of the isthmus where he first observed the Pacific. In 1520, navigator Ferdinand Magellan and his crew were the first to cross

6160-439: The ocean's surface. One of the most dramatic is the Great Barrier Reef off northeastern Australia with chains of reef patches. A second island type formed of coral is the uplifted coral platform, which is usually slightly larger than the low coral islands. Examples include Banaba (formerly Ocean Island) and Makatea in the Tuamotu group of French Polynesia . The volume of the Pacific Ocean, representing about 50.1 percent of

6248-409: The planet's total surface area, larger than its entire land area (148,000,000 km (57,000,000 sq mi)). The centers of both the Water Hemisphere and the Western Hemisphere , as well as the oceanic pole of inaccessibility , are in the Pacific Ocean. Ocean circulation (caused by the Coriolis effect ) subdivides it into two largely independent volumes of water that meet at the equator ,

6336-581: The quest for Terra Australis ("the [great] Southern Land"), Spanish explorations in the 17th century, such as the expedition led by the Portuguese navigator Pedro Fernandes de Queirós , arrived at the Pitcairn and Vanuatu archipelagos, and sailed the Torres Strait between Australia and New Guinea, named after navigator Luís Vaz de Torres . Dutch explorers, sailing around southern Africa, also engaged in exploration and trade; Willem Janszoon , made

6424-528: The rate of dissolution increases inward to its maximum at the center of the island. As a result, a saucer shaped island with a raised rim forms. When relative sea level submerges the island again, the rim provides a rocky core on which coral grow again to form the islands of an atoll and the flooded bottom of the saucer forms the lagoon within them. The word atoll comes from the Dhivehi word atholhu ( އަތޮޅު , pronounced [ˈat̪oɭu] ). Dhivehi

6512-505: The settlement of Buka by 32,000 B.P. and Manus by 25,000 B.P. Journeys of 180 kilometres (110 mi) and 230 kilometres (140 mi) are involved, respectively. The descendants of these migrations today are the Negritos , Melanesians , and Indigenous Australians . Their populations in maritime Southeast Asia , coastal New Guinea , and Island Melanesia later intermarried with the incoming Austronesian settlers from Taiwan and

6600-504: The southeast of Hawaii is computed, and if the region is more than 0.5 °C (0.9 °F) above or below normal for that period, then an El Niño or La Niña is considered in progress. In the tropical western Pacific, the monsoon and the related wet season during the summer months contrast with dry winds in the winter which blow over the ocean from the Asian landmass. Worldwide, tropical cyclone activity peaks in late summer, when

6688-533: The subsidence of an island until MIS-11, Mid-Brunhes, long after the many the former islands had been completely submerged and buried by flat topped reefs during the Neogene. Atolls are the product of the growth of tropical marine organisms, and so these islands are found only in warm tropical waters. Volcanic islands located beyond the warm water temperature requirements of hermatypic (reef-building) organisms become seamounts as they subside, and are eroded away at

6776-415: The subsidence of an oceanic island of either volcanic or nonvolcanic origin below sea level. Then, when relative sea level drops below the level of the flat surface of coral reef, it is exposed to the atmosphere as a flat topped island which is dissolved by rainfall to form limestone karst . Because of hydrologic properties of this karst, the rate of dissolution of the exposed coral is lowest along its rim and

6864-696: The surface. An island that is located where the ocean water temperatures are just sufficiently warm for upward reef growth to keep pace with the rate of subsidence is said to be at the Darwin Point . Islands in colder, more polar regions evolve toward seamounts or guyots ; warmer, more equatorial islands evolve toward atolls, for example Kure Atoll . However, ancient atolls during the Mesozoic appear to exhibit different growth and evolution patterns. Coral atolls are important as sites where dolomitization of calcite occurs. Several models have been proposed for

6952-804: The tropics and Antarctica, which records the coldest temperature readings on the planet. In the Southern hemisphere, because of the stormy and cloudy conditions associated with extratropical cyclones riding the jet stream, it is usual to refer to the Westerlies as the Roaring Forties, Furious Fifties and Shrieking Sixties according to the varying degrees of latitude. The ocean was first mapped by Abraham Ortelius ; he called it Maris Pacifici following Ferdinand Magellan 's description of it as "a pacific sea" during his circumnavigation from 1519 to 1522. To Magellan, it seemed much more calm (pacific) than

7040-587: The vast Pacific Ocean . Their last known position report was near the Nukumanu Islands, about 800 miles (1,300 km) into the flight. The land resources of the Nukumanu people are quite few and they grow a kind of taro and bananas . Coconuts are an integral part of the islanders' diet with the soft inside being a staple food and coconut flesh being consumed with raw fish and clams. They are also competent fishermen, who dive for bêche-de-mer in

7128-430: The volcanic island becomes extinct and eroded as it subsides completely beneath the surface of the ocean. As the volcanic island subsides, the coral fringing reef becomes a barrier reef that is detached from the island. Eventually, reef and the small coral islets on top of it are all that is left of the original island, and a lagoon has taken the place of the former volcano. The lagoon is not the former volcanic crater. For

7216-586: The west, and Drake Passage and the Strait of Magellan link the Pacific with the Atlantic Ocean on the east. To the north, the Bering Strait connects the Pacific with the Arctic Ocean . As the Pacific straddles the 180th meridian , the West Pacific (or western Pacific , near Asia) is in the Eastern Hemisphere , while the East Pacific (or eastern Pacific , near the Americas) is in

7304-534: The width of the Pacific with precision for the first time in history. One of the earliest voyages of scientific exploration was organized by Spain in the Malaspina Expedition of 1789–1794. It sailed vast areas of the Pacific, from Cape Horn to Alaska, Guam and the Philippines, New Zealand, Australia, and the South Pacific. Growing imperialism during the 19th century resulted in the occupation of much of Oceania by European powers, and later Japan and

7392-688: The world are Elizabeth Reef at 29°57′ S, and nearby Middleton Reef at 29°27′ S, in the Tasman Sea , both of which are part of the Coral Sea Islands Territory. The next southerly atoll is Ducie Island in the Pitcairn Islands Group, at 24°41′ S. The atoll closest to the Equator is Aranuka of Kiribati. Its southern tip is just 13 km (8 mi) north of the Equator. Bermuda is sometimes claimed as

7480-434: The world's oceanic water, has been estimated at some 714 million cubic kilometers (171 million cubic miles). Surface water temperatures in the Pacific can vary from −1.4 °C (29.5 °F), the freezing point of seawater, in the poleward areas to about 30 °C (86 °F) near the equator. Salinity also varies latitudinally, reaching a maximum of 37 parts per thousand in the southeastern area. The water near

7568-533: Was led by Professor William Johnson Sollas of the University of Oxford . Geologists included Walter George Woolnough and Edgeworth David of the University of Sydney . Professor Edgeworth David led the expedition in 1897. The third expedition in 1898 was led by Alfred Edmund Finckh. Pacific Ocean Main five oceans division: Further subdivision: The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions . It extends from

7656-402: Was published in 1931. Atoll An atoll ( / ˈ æ t . ɒ l , - ɔː l , - oʊ l , ə ˈ t ɒ l , - ˈ t ɔː l , - ˈ t oʊ l / ) is a ring-shaped island, including a coral rim that encircles a lagoon . There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical parts of the oceans and seas where corals can develop. Most of

7744-583: Was the first to show the Americas separating two distinct oceans. Later, the Diogo Ribeiro map of 1529 was the first to show the Pacific at about its proper size. (Inhabited dependent territories are denoted by the asterisk (*), with names of the corresponding sovereign states in round brackets. Associated states in the Realm of New Zealand are denoted by the hash sign (#).) Territories with no permanent civilian population. The Pacific Ocean has most of

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