Oceania is the name for the island world of the Pacific north and east of Australia. The more than 7,500 islands together cover a land area of almost 1.3 million square kilometers (which is roughly three and a half times the area of Germany) and extend over a sea area of around 70 million square kilometers. Around 2100 of the islands are inhabited. 16.5 million people live there. Together with Australia, Oceania forms the greater continental region of Australia and Oceania.
The extent of the area belonging to Oceania is defined differently. In the most common German-language definition, only Polynesia, Melanesia (with New Guinea) and Micronesia belong to Oceania. According to Countryaah, both New Zealand and Hawaii are assigned to Polynesia, as both were settled by Polynesians, who were of great importance for their cultural development. This is also true today, although New Zealand has strong European traits due to European immigration and Hawaii is part of the American economic area. The classification thus includes the East Asian island chains and those of the Malay Archipelago that show a different cultural landscape development with different historical, economic and social characteristics.
The east of the Malay Archipelago is rarely included. Occasionally – and especially in the English-speaking world and here – are Australia and Oceania also shortened as Oceania (Oceania), respectively.
The area owes its peculiar nomenclature to the apparent distance to other continents. In order to unite the cultural identity of the indigenous peoples of the Pacific world in one term, the name Austronesia was previously used for the South Sea islands inhabited by Māori and other Polynesian peoples. Gradually the term was extended to other areas.
In English, the term transoceania is also used. This term originated mainly for economic reasons in Australia and New Zealand and describes an area from northern Australia via Indonesia to the southern border of the Philippines and the far west of the Pacific islands. The region is of great importance for the industrialized countries in the south as a trade route to the developing and emerging countries of East and Southeast Asia, as well as a source of raw materials, a location for cheap production and a sales market.
The term ” South Sea ” was coined in 1513 by Vasco Núñez de Balboa, when he had crossed the isthmus of Panama and called the sea (Pacific) in front of him Mar del sur (“South Sea”), as he looked south from his location looked at the sea. Central island groups are the Society Islands (French Polynesia / Tahiti), the Samoa Archipelago and the Fiji Islands. The term South Seas is often used synonymously with Oceania and in the narrower sense with Polynesia (triangle with the corner points Hawaii,New Zealand and Easter Island). Other terms derived from this are commonly used, such as the South Pacific or South Pacific island area. In the past, these often appeared in political vocabulary as self-chosen terms (e.g. South Pacific Forum, South Pacific Commission, University of the South Pacific). Many of these names have been changed in recent years to give meaning to the entire Pacific region.
Oceania is not a continent in the geological sense, as only New Caledonia, New Zealand, New Guinea and Tasmania consist of the continental crust of the former continent Gondwana: New Zealand, New Caledonia and the Lord Howe threshold with the Lord Howe archipelago form a large part of the former continental shelf of Gondwana, the microcontinent Zealandia. New Guinea is only separated from Australia by the shallow Arafura Sea. Even during the last Ice Age, they formed a contiguous land mass called Sahul, because at that time the water level in the Pacific was about 100 m lower than it is today.
Most of the islands of Oceania are volcanic peaks in the average 4000 m deep Pacific Ocean, often recognizable by volcanic craters on land. Sometimes the volcanoes only reach just below the sea surface and are expanded by corals to form reefs and flat islands. Often there is a volcanic islands of a belt of coral reefs are framed or rock formations from the formed of coral limestone have. Cave structures are often found here.
Volcanic activities are triggered by geological processes in the oceanic crust. The movements of the lithospheric plates in the Pacific are also the cause of the so-called Pacific Ring of Fire, on which many islands were formed, especially on its western edge. Volcanism at hotspots resulted in long chain of islands lying far in the ocean, such as the Hawaii-Emperor chain with the islands of the Kure Atoll, the Midway Islands and the Hawaiian Islands as the end point.
Deep-sea trenches, island arches and sometimes lake basins were created where subduction occurs, for example on the Pacific plate.
At the height of the equator, the equatorial countercurrent runs from west to east in the Pacific. To the north, at the height of Hawaii, the North Equatorial Current flows from east to west. In New Guinea it turns into a northward current, flows east of the Philippines as Kuroshio and creates a huge vortex in the area of Micronesia. Part of the ocean current leaves the eddy eastward to flow to the coast of North America and return to its beginning as the north equatorial current.
The south equatorial current runs south of the equator, also from east to west. This is fed by the cold Humboldt Current on the west coast of South America and partially merges into the East Australian Current, which flows along the east coast of Australia and meets New Zealand.
From there an eastward current runs to South America, which is composed of warm equatorial water and cold water of the Antarctic Circumpolar Current, which runs south from Australia and New Zealand. As a result, New Zealand is surrounded by a warm ocean current in the north and a cold ocean current in the south.