Low islands or AtollsLow islands are called atolls if they consist of a ring of land or islets surrounding a shallow lagoon. Their land consists of broken pieces of coral and white sand. Many such low islands also have patches of fertile soil formed by slowly accumulated plant matter, airborne dust, and fertilizers applied by farmers. Kwajalein in the Marshall Islands is the largest atoll in the world. It consists of 90 islets on the rim of a lagoon of about 650 square miles. Many low islands are at risk from storms, tsunamis, and rising sea levels due to global warming.

Agriculture and Fishing

Major sources of individual and family income in Oceania include agriculture, fishing, mining, and tourism. Also important is the money sent home by workers who have found jobs in foreign countries, often as plantation or mine laborers. Foreign aid, fishing-rights contracts, and agricultural or mining exports are important sources of income to many island governments, which are generally the largest employers in the region.

Spear fishermen work in the sea on the island of Aitutaki, one of the Cook Islands of the South Pacific.

Most subsistence crops produce edible roots or tubers such as taro and its relatives, which are grown in warm places. Sweet potatoes are found at higher altitudes or where it is colder, as in New Zealand. Coconut is very important. Its cream is used in cooking, and its dried meat, called copra, is the source of coconut oil. What is left is fed to pigs and other livestock, which may also graze on vegetation beneath the coconut trees. Chickens are also raised. Besides coconut palms, other common useful trees include bananas, sago palms in Melanesia, and breadfruit. Like many plants of Oceania, the breadfruit tree is not only grown for its fruit but is used to make other materials: the wood is good for building houses, the latex is used to caulk boats, and the leaf can be used as a plate.

MiningMining is important, though Oceania's mineral reserves are small by world standards. In the 19th century guano, a natural fertilizer consisting of the manure of seabirds was mined on many low islands. Today phosphate rock is taken from raised limestone islands. For decades, the main source of phosphate was Nauru, but its center has been transformed into a wasteland. New Caledonia is among the world's leading producers of nickel, so its economy is influential in the region. Gold deposits have been found in limited quantities, with Papua New Guinea leading the region in exports. New Zealand also mines coal, natural gas, and petroleum, as well as minerals used in construction and industry.

Decades of phosphate mining devastated the center of the island of Nauru.

Oceania

The geographic region Oceania includes roughly 10,000 islands in the Pacific Ocean, mainly in the western and central portions. Oceania covers about 20 million square miles or roughly one third of the enormous Pacific Ocean. Yet the total land area of the islands is very small—only some 324,000 square miles. Papua New Guinea and New Zealand represent nine tenths of the total. The other islands cover merely 41,000 square miles - about the extent of Portugal or a third of Ecuador. Most of the islands appear simply as isolated specks on a map of the ocean, and some are mere rocks. Some of the islands are crowded with people, but others are total wilderness. About 14 million people live in the region, nearly three quarters of them in New Zealand and Papua New Guinea.

Polynesia

The name Polynesia means “many islands”; it applies mainly to islands with similar cultures that lie in the central Pacific. Among the countries of Polynesia are New Zealand , Tuvalu, Tonga, and Samoa. Also included are France's overseas territory Wallis and Futuna and overseas country French Polynesia, which incorporates the Tuamotu, Gambier, Society, Austral, Leeward, and Marquesas islands. The New Zealand dependencies of Tokelau, the Cook Islands, and Niue; the United States dependencies of American Samoa, Jarvis, Palmyra, and Kingman Reef, among others; and the British-controlled Pitcairn Island are also part of Polynesia. Chile administers Easter Island, and Hawaii is a U.S. state.

Ayers Rock

One of Australia's most famous landmarks, Uluru/Ayers Rock is a giant mass of weathered sandstone located in the southwestern part of the Northern Territory . It is of great cultural significance, as shallow caves at the base of the rock are sacred to several Aboriginal tribes. Within the caves are many Aboriginal carvings and paintings. The rock is part of the larger Uluru–Kata Tjuta National Park (formerly Ayers Rock–Mount Olga National Park). The park was

declared a UNESCO World Heritage site in 1987 and is among Australia's most popular tourist destinations.

Uluru/Ayers Rock is composed of a type of coarse-grained sandstone known as arkose. The rock appears in different shades of pinks, reds, oranges, and browns depending on the position of the sun. At sunset it is a fiery orange-red. One of the largest rocks in the world, it rises 1,100 feet above the surrounding desert plain. Roughly oval in shape, it is about 2.2 miles long by 1.5 miles wide. Over time, rain and wind have eroded the rock, leaving the lower slopes fluted and the top carved by gullies and basins. After rainstorms (which are infrequent in this arid region), the gullies and basins produce large waterfalls.

The rock has long been known to the Aborigines who live in the area. The Aboriginal name for the rock is Uluru. The first non-indigenous Australian to see the rock, in 1873, was the explorer William Gosse. He named

the rock Ayers after the former South Australian premier Sir Henry Ayers. In 1985 the government granted official ownership of the rock to the Aborigines, who then leased the rock and the national park to the government for 99 years. The rock's name was officially changed to Ayers Rock/Uluru in 1993 and to Uluru/Ayers Rock in 2002.

Tsunami The word tsunami is a Japanese word, represented by two characters: tsu, meaning “harbor,” and nami, meaning “wave.” Although tsunamis are often referred to as tidal waves, this is a misnomer. Tides are generated by the

gravitational effects of the moon, sun, and planets. Tsunamis are caused by a sudden or impulsive disturbance that vertically displaces the water column. They are not connected to tides, though the tide level affects the impact a tsunami has as it reaches the shore.

Tsunamis are most commonly generated by underwater earthquakes, which are caused when the seafloor abruptly deforms. The Earth's outer shell is made up of several slowly moving plates. Most earthquakes occur near the plate boundaries as the plates move over, along, or away from each other. Earthquakes release a large amount of energy, and in the ocean the violent shaking of the seafloor displaces the water. If a large earthquake occurs near the surface of the ocean floor, the resulting energy transfer to the water column produces great waves. Most tsunamis result from earthquakes with a magnitude greater than 6.5 on the Richter scale and that occur less than 30 miles beneath the seafloor. Volcanic eruptions, landslides, and other great disturbances of the ocean water can also generate tsunamis.

The deadliest tsunami in recorded history occurred in the Indian Ocean in December 2004. It was generated by an extremely large earthquake off the northwest coast of the Indonesian island of Sumatra. The tsunami devastated the islands and coasts of more than 10 countries in southern Asia and eastern Africa. The waves washed away entire villages and killed more than 200,000 people. The death toll was the highest in Indonesia, Sri Lanka, India, and Thailand.

Other large tsunamis of recent history include one that ravaged the northwestern coast of Papua New Guinea in 1998, killing more than 2,100 people, and one that occurred in 1976 in the Philippines, killing about 8,000 people. Another major earthquake-generated tsunami took place in Chile in 1960. With a magnitude of 9.5, the earthquake was the largest ever recorded. The tsunami it generated was responsible for about 2,000 deaths along the Chile-Peru coast. After devastating the coastline of South America, the tsunami traveled for 15 hours across the Pacific to Hilo, Hawaii, claiming an additional 61 lives, and for 22 hours to Japan, killing another 122 people. In 1883 the eruptions of the volcano Krakatoa between the islands of

Sumatra and Java created a tsunami that

killed more than 36,000 people.

Great Barrier Reef in the Coral Sea, off the coast of Queensland, Australia, lies the Great Barrier Reef, one of the natural wonders of the world. A barrier reef is a long, narrow, mostly submerged coral formation that lies parallel to the shoreline of a landmass. The Great Barrier Reef is the largest complex of coral reefs, shoals, and islets in the world. Despite its name, it is not a single reef. It actually includes

some 2,900 reefs, of which about 800 are fringing reefs (which form closer to shorelines). It stretches more than 1,250 miles from northwest to southeast, a length comparable to that of the Pacific coast of the United States. Its area is about 135,000 square miles.

The Great Barrier Reef is composed of the skeletal remains of millions of tiny

corals. The reef was built upon a shallow fringe of continental shelf in waters warm enough for the coral to flourish. The variety of sea life on and around the Great Barrier Reef is extraordinary. Each species occupies a specific niche, or relationship to other organisms in the reef community. Besides

corals, other forms of invertebrate reef life include anemones, worms, snails, lobsters, crayfish, prawns, jellyfish, and giant clams. More than 1,500 species of saltwater fishes, sea birds live along the reef. Many of the small fishes have brilliant colors and unusual shapes. Plant life above the surface of the water is limited, with only about 30 to 40 species.

The Great Barrier Reef's abundance of sea life is a major tourist attraction for Australia. Big game fishing is done on the open waters nearby. The irregularities of the seafloor immediately surrounding the reef make commercial netting of fish difficult, so it is carried out on a limited basis. Sea turtles that were once captured for food are now protected by law from commercial exploitation. Concern for the reefs' preservation has made tourism and fishing there controversial.

The Great Barrier Reef first became known to the Western world through the explorations of Capt. James Cook. In 1770

his ship the Endeavour ran aground on a reef 20 miles from land Exploration of the reef, begun by Cook, continued throughout the 19th century. In 1928–29 a scientific survey extensively studied coral physiology and the ecology of the reefs. Scientists set up a modern laboratory on Heron Island to study the reefs in 1951. The United Nations

Educational, Scientific and Cultural Organization (UNESCO) named the Great Barrier Reef a World Heritage Site in 198 1.

Melanesia means “islands inhabited by blacks”—a term introduced by racial-minded Europeans, though not all Melanesians have dark skin. Among the independent nations of Melanesia are Fiji, the Solomon Islands, and Vanuatu. Melanesia also includes Papua New Guinea, which occupies the eastern part of the enormous island of New Guinea, as well as the Bismarck Archipelago and other nearby islands. The western part of New Guinea is often excluded from Oceania because it is part of Indonesia. New Caledonia is a French overseas country.