Monday, October 7, 2013

Geography of Brazil

The country of Brazil occupies roughly half of South America, bordering the Atlantic Ocean. Brazil covers a total area of 8,514,215 km2 (3,287,357 sq mi) which includes 8,456,510 km2 (3,265,080 sq mi) of land and 55,455 km2 (21,411 sq mi) of water. The highest point in Brazil is Pico da Neblina at 2,994 m (9,823 ft). Brazil is bordered by the countries of Argentina, Bolivia, Colombia, French Guiana, Guyana, Paraguay, Peru, Suriname, Uruguay and Venezuela.
Much of the climate is tropical, with the south being relatively temperate. The largest river in Brazil, and one of the longest in the world, is the Amazon. The rainforest that covers the Amazon Basin constitutes almost half of the rainforests on Earth.
Brazil possesses the archipelago of Fernando de Noronha, located 350 kilometres (217 mi) northeast of its "horn", and several small islands and atolls in the Atlantic - Abrolhos, Atol das Rocas, Penedos de São Pedro e São Paulo, Trindade, and Martim Vaz. In the early 1970s, Brazil claimed a territorial sea extending 362 kilometres (225 mi) from the country's shores, including those of the islands.
On Brazil's east coast, the Atlantic coastline extends 7,367 kilometres (4,578 mi). In the west, in clockwise order from the south, Brazil has 15,719 kilometres (9,767 mi) of borders with Uruguay, Argentina, Paraguay, Bolivia, Peru, Colombia, Venezuela, Guyana, Suriname, and French Guiana. The only South American countries with which Brazil does not share borders are Chile and Ecuador. A few short sections are in question, but there are no true major boundary controversies with any of the neighboring countries.

Brazil has six major ecosystems: the Amazon Basin, a tropical rainforest system; the Pantanal bordering Paraguay and Bolivia, a tropical wetland system; the Cerrado, a savanna system that covers much of the center of the country; the Caatinga or thorny scrubland habitat of the Northeast; the Atlantic Forest (Mata Atlântica) that extends along the entire coast from the Northeast to the South; and the Pampas or fertile lowland plains of the far South.
In contrast to the Andes, which rose to elevations of nearly 7,000 metres (22,966 ft) in a relatively recent epoch and inverted the Amazon's direction of flow from westward to eastward, Brazil's geological formation is very old. Precambrian crystalline shields cover 36% of the territory, especially its central area. The dramatic granite sugarloaf mountains in the city of Rio de Janeiro are an example of the terrain of the Brazilian shield regions, where continental basement rock has been sculpted into towering domes and columns by tens of millions of years of erosion, untouched by mountain-building events.
The principal mountain ranges average elevations just under 2,000 metres (6,562 ft). The Serra do Mar Range hugs the Atlantic coast, and the Serra do Espinhaço Range, the largest in area, extends through the south-central part of the country. The highest mountains are in the Tumucumaque, Pacaraima, and Imeri ranges, among others, which traverse the northern border with the Guianas and Venezuela.
In addition to mountain ranges (about 0.5% of the country is above 1,200 m or 3,937 ft), Brazil's Central Highlands include a vast central plateau (Planalto Central). The plateau's uneven terrain has an average elevation of 1,000 metres (3,281 ft). The rest of the territory is made up primarily of sedimentary basins, the largest of which is drained by the Amazon and its tributaries. Of the total territory, 41% averages less than 200 metres (656 ft) in elevation. The coastal zone is noted for thousands of kilometers of tropical beaches interspersed with mangroves, lagoons, and dunes, as well as numerous coral reefs.
Topographic map of Brazil
Brazil has one of the world's most extensive river systems, with eight major drainage basins, all of which drain into the Atlantic Ocean. Two of these basins—the Amazon and Tocantins-Araguaia account for more than half the total drainage area. The largest river system in Brazil is the Amazon, which originates in the Andes and receives tributaries from a basin that covers 45.7% of the country, principally the north and west. The main Amazon river system is the Amazonas-Solimões-Ucayali axis (the 6,762-kilometre (4,202 mi)-long Ucayali is a Peruvian tributary), flowing from west to east. Through the Amazon Basin flows one-fifth of the world's fresh water. A total of 3,615 kilometres (2,246 mi) of the Amazon are in Brazilian territory. Over this distance, the waters decline only about 100 metres (330 ft). The major tributaries on the southern side are, from west to east, the Javari, Juruá, Purus (all three of which flow into the western section of the Amazon called the Solimões), Madeira, Tapajós, Xingu, and Tocantins. On the northern side, the largest tributaries are the Branco, Japurá, Jari, and Rio Negro. The above-mentioned tributaries carry more water than the Mississippi (its discharge is less than one-tenth that of the Amazon). The Amazon and some of its tributaries, called "white" rivers, bear rich sediments and hydrobiological elements. The black-white and clear rivers—such as the Negro, Tapajós, and Xingu—have clear (greenish) or dark water with few nutrients and little sediment.
The major river system in the Northeast is the Rio São Francisco, which flows 1,609 kilometres (1,000 mi) northeast from the south-central region. Its basin covers 7.6% of the national territory. Only 277 kilometres (172 mi) of the lower river are navigable for oceangoing ships. The Paraná system covers 14.5% of the country. The Paraná flows south among the Río de la Plata Basin, reaching the Atlantic between Argentina and Uruguay. The headwaters of the Paraguai, the Paraná's major eastern tributary, constitute the Pantanal, the largest contiguous wetlands in the world, covering as much as 230,000 square kilometres (89,000 sq mi).

Below their descent from the highlands, many of the tributaries of the Amazon are navigable. Upstream, they generally have rapids or waterfalls, and boats and barges also must face sandbars, trees, and other obstacles. Nevertheless, the Amazon is navigable by oceangoing vessels as far as 3,885 kilometres (2,414 mi) upstream, reaching Iquitos in Peru. The Amazon river system was the principal means of access until new roads became more important. Hydroelectric projects are Itaipu, in Paraná, with 12,600 MW; Tucuruí, in Pará, with 7,746 MW; and Paulo Afonso, in Bahia, with 3,986 MW.

Natural resources

Natural resources include: bauxite, gold, iron ore, manganese, nickel, phosphates, platinum, tin, Clay, uranium, petroleum, hydropower and timber.

Rivers and lakes

Main Hydrographic Regions of Brazil
According to organs of the Brazilian government there are 12 major hydrographic regions in Brazil. Seven of these are river basins named after their main rivers; the other five are groupings of various river basins in areas which have no dominant river.
  • 5 coastal Hydrographic Regions based on regional groupings of minor river basins (listed from north to south):
    • Atlântico Nordeste Ocidental (Western North-east Atlantic)
    • Atlântico Nordeste Oriental (Eastern North-east Atlantic)
    • Atlântico Leste (Eastern Atlantic)
    • Atlântico Sudeste (South-east Atlantic)
    • Atlântico Sul (South Atlantic)
The Amazon River is the widest and second longest river (behind the Nile) in the world. This huge river drains the greater part of the world's rainforests. Another major river, the Paraná, has its source in Brazil. It forms the border of Paraguay and Argentina, then winds its way through Argentina and into the Atlantic Ocean, along the southern coast of Uruguay. The HBV hydrology transport model has been used to analyze certain pollutant transport in Brazil's river systems. The Amazon is full of eroded soil.

Soils and vegetation

The Amazon Rainforest
Brazil's tropical soils produce 70 million tons of grain crops per year, but this output is attributed more to their extension than their fertility. Despite the earliest Portuguese explorers' reports that the land was exceptionally fertile and that anything planted grew well, the record in terms of sustained agricultural productivity has been generally disappointing. High initial fertility after clearing and burning usually is depleted rapidly, and acidity and aluminum content are often high. Together with the rapid growth of weeds and pests in cultivated areas, as a result of high temperatures and humidity, this loss of fertility explains the westward movement of the agricultural frontier and slash-and-burn agriculture; it takes less investment in work or money to clear new land than to continue cultivating the same land. Burning also is used traditionally to remove tall, dry, and nutrient-poor grass from pasture at the end of the dry season. Until mechanization and the use of chemical and genetic inputs increased during the agricultural intensification period of the 1970s and 1980s, coffee planting and farming in general moved constantly onward to new lands in the west and north. This pattern of horizontal or extensive expansion maintained low levels of technology and productivity and placed emphasis on quantity rather than quality of agricultural production.
The largest areas of fertile soils, called terra roxa (red earth), are found in the states of Paraná and São Paulo. The least fertile areas are in the Amazon, where the dense rain forest is. Soils in the Northeast are often fertile, but they lack water, unless they are irrigated artificially.
In the 1980s, investments made possible the use of irrigation, especially in the Northeast Region and in Rio Grande do Sul State, which had shifted from grazing to soy and rice production in the 1970s. Savanna soils also were made usable for soybean farming through acidity correction, fertilization, plant breeding, and in some cases spray irrigation. As agriculture underwent modernization in the 1970s and 1980s, soil fertility became less important for agricultural production than factors related to capital investment, such as infrastructure, mechanization, use of chemical inputs, breeding, and proximity to markets. Consequently, the vigor of frontier expansion weakened.
The variety of climates, soils, and drainage conditions in Brazil is reflected in the range of its vegetation types. The Amazon Basin and the areas of heavy rainfall along the Atlantic coast have tropical rain forest composed of broadleaf evergreen trees. The rain forest may contain as many as 3,000 species of flora and fauna within a 2.6-square-kilometre (1 sq mi) area. The Atlantic Forest is reputed to have even greater biological diversity than the Amazon rain forest, which, despite apparent homogeneity, contains many types of vegetation, from high canopy forest to bamboo groves.
In the semiarid Northeast, caatinga, a dry, thick, thorny vegetation, predominates. Most of central Brazil is covered with a woodland savanna, known as the cerrado (sparse scrub trees and drought-resistant grasses), which became an area of agricultural development after the mid-1970s. In the South (Sul), needle-leaved pinewoods (Paraná pine or araucaria) cover the highlands; grassland similar to the Argentine pampa covers the sea-level plains. The Mato Grosso swamplands (Pantanal Mato-grossense) is a Florida-sized plain in the western portion of the Center-West (Centro-Oeste). It is covered with tall grasses, bushes, and widely dispersed trees similar to those of the cerrado and is partly submerged during the rainy season.
Brazil, which is named after reddish dyewood (pau brasil), has long been famous for the wealth of its tropical forests. These are not, however, as important to world markets as those of Asia and Africa, which started to reach depletion only in the 1980s. By 1996 more than 90% of the original Atlantic forest had been cleared, primarily for agriculture, with little use made of the wood, except for araucaria pine in Paraná.
The inverse situation existed with regard to clearing for wood in the Amazon rain forest, of which about 15% had been cleared by 1994, and part of the remainder had been disturbed by selective logging. Because the Amazon forest is highly heterogeneous, with hundreds of woody species per hectare, there is considerable distance between individual trees of economic value, such as mahogany and cerejeira. Therefore, this type of forest is not normally cleared for timber extraction but logged through high-grading, or selection of the most valuable trees. Because of vines, felling, and transportation, their removal causes destruction of many other trees, and the litter and new growth create a risk of forest fires, which are otherwise rare in rain forests. In favorable locations, such as Paragominas, in the northeastern part of Pará State, a new pattern of timber extraction has emerged: diversification and the production of plywood have led to the economic use of more than 100 tree species.

Starting in the late 1980s, rapid deforestation and extensive burning in Brazil received considerable international and national attention. Satellite images have helped document and quantify deforestation as well as fires, but their use also has generated considerable controversy because of problems of defining original vegetation, cloud cover, and dealing with secondary growth and because fires, as mentioned above, may occur in old pasture rather than signifying new clearing. Public policies intended to promote sustainable management of timber extraction, as well as sustainable use of nontimber forest products (such as rubber, Brazil nuts, fruits, seeds, oils, and vines), were being discussed intensely in the mid-1990s. However, implementing the principles of sustainable development, without irreversible damage to the environment, proved to be more challenging than establishing international agreements about them