Amazon Facts | Project Amazonas Project Amazonas Amazon Facts Amazon Facts Amaze (or bore) your friends and colleagues with some Amazon trivia. Who knows, it might even win you big bucks someday on a game show! The Amazon IS the world's greatest river. The Nile of Africa may be slightly longer, depending on how you measure each river, but for many other reasons the Amazon River is the undisputed title holder - the greatest river on the planet, in the solar system, and perhaps even in the Milky Way galaxy (at least no-one from planets orbiting Betelgeuse or Antares has yet provided convincing evidence that they have a bigger river on their planet!). Read on! If size is important to you... The average discharge of water into the Atlantic Ocean by the Amazon is approximately 175,000 m3 per second, or between 1/5th and 1/6th of the total discharge into the oceans of all of the world's rivers! This discharge is 4-5 times that of the Congo River (the second largest in ocean discharge), and 10 times that of the Mississippi.

The Rio Negro, a tributary of the Amazon, is the second largest river in the world in terms of water flow, and is 100 meters (over 300 feet) deep and 14 kilometers (~9 miles) wide near its mouth at Manaus, Brazil. Raindrops keep falling on my head! Average rainfall across the whole Amazon basin is approximately 2300 mm (or ~7.5') annually. In some areas of the northwest portion of the Amazon basin, yearly rainfall can exceed 6000 mm (almost 20')! Where does all that water go? The water discharged into the Atlantic Ocean is actually only about 1/3rd of the water that falls in the Amazon basin as rain. Where does the other 2/3rds go? Up to half of the rainfall in some areas may never reach the ground, being intercepted by the forest and re-evaporated into the atmosphere. Additional evaporation occurs from ground and river surfaces, or is released into the atmosphere by transpiration from plant leaves.

All of this moisture re-enters the water cycling system of the Amazon, and a given molecule of water may be "re-cycled" many times between the time that it leaves the surface of the Atlantic Ocean and is carried by the prevailing westerly winds into the Amazon basin, to the time that it is carried back to the ocean by the Amazon River. The Andes Mountains that border the west side of the Amazon help to ensure that most of the moisture stays in the system - very little is carried by the prevailing winds over the Andes to the Pacific Ocean. A long and winding river road. The total length of the Amazon River from its source springs in the Andes (taking the Ucayali River as the continuation of the main river into the Andes), is estimated at 6518 km ( ~4075 miles) (not including all river bends, and measuring the short distance around Marajó Island in the mouth of the Amazon). This is exceeded only by the Nile River (including the Kagera River) of Africa with a total length of 6671 km (4170 miles).

If you measure the long-way around Marajo Island, however, the Amazon is slightly longer than the Nile! The Amazon headwaters are located high in the Andes at an elevation of about 5,200 meters (17,000 feet), and only 190 kilometers (120 miles) from the Pacific Ocean. Like mother, like daughters.... Two of the tributaries of the Amazon, the Juruá and the Madeira Rivers, are both over 3,300 km (2,060 miles) long. About 1,100 other sizeable tributaries empty into the Amazon River. Talk about a big mouth! The mouth of the Amazon is over 320 km wide (approximately 200 miles), and contains the worlds largest freshwater island, Marajó Island, with an area of 48,000 km2 (about the size of Switzerland). Momma was not a Rolling Stone! After leaving the Andes, the elevational gradient of the Amazon is very low.

Iquitos, Peru is some 3,600 km (2,250 miles) from the Atlantic, yet the river-level at low-water season is only about 100 m (a bit more than 300') above sea-level, and the slope is around 2 cm (less than one inch) vertical change per kilometer. In the lower Amazon, at the mouth of Rio Negro and still 1,500 km from the Atlantic, the river-level at low-water season is only 15 m (~47') above sea-level, and the slope is about 1 cm per kilometer. You won't find any white-water rapids along the main channel of the Amazon, though the sheer weight of the mass of water moves it along at a surprising speed. NEWS FLASH!! Rumpelstiltskin Drowns in Slow Flood. The Amazon is not a good place to fall into a long deep sleep on the river bank! Seasonal water levels can vary up to 20 meters (65 feet) in the middle Amazon region.

Towards the mouth of the Amazon, the yearly change becomes less and less, but even near the mouth of the Amazon (at the Rio Xingu), it is still 4 meters (12 feet). In the Iquitos region of Peru, the annual change in river levels is about 15 meters (~50'). Flooded but not drowned. The seasonal variation in water levels means that huge areas along the major rivers in the Amazon basin are flooded annually. The total area of flooded, or varzea, forest is between 50-60,000 km2, or about 4% of the total area of the Amazon rainforest. These flooded forest areas may extend as much as 80 kilometers (50 miles) from the main river channels, and the forest vegetation of the varzea is well adapted to being seasonally flooded. The structure and species composition of the varzea is very different from non-flooded upland (or terra firme) forest areas. Varzea forest areas are critical to the freshwater fisheries of the Amazon Basin. Go with the flow. Despite the low slope of the Amazon, the river currents can be surprisingly strong.

In the lower Amazon (with the lowest slope), current speeds range from 0.5-1.0 meters per second at low water, and twice that at flood stage. In localized areas, current speeds can reach as high as 3 meters (9.8 feet) per second. Ships on a submarine river? The width of the Amazon at Iquitos, Peru (3,600 km/2,250 miles from the ocean) is about 2 km. Ocean-going ships can easily access the Port of Iquitos at high water, as the mean depth of the current-canal of the Amazon is between 40 and 50 m (or up to 150+ feet deep), and in places, over 100 m (over 300 feet) deep. Even hundreds of miles away from the ocean, sections of the bottom of the river channel actually lie below sea level! World's Biggest Outhouse! In the Atlantic Ocean beyond the mouth of the Amazon, and resting on the continental shelf, the Amazon sediment cone has a length of about 680 km and a width of 250 km.

These fine grained deposits (mostly clay/mud particles) on the ocean floor are over 11,000 meters (36,000 feet) thick. This is mostly sediment that has been carried downriver from the Andes Mountains, the Guianan Shield (to the North) and the Brazilian Shield (to the south), by the river current, and which settled out of the water column once the river current dissipated into the waters of the Atlantic Ocean. World's Biggest Washtub. The Amazon basin (the watershed of the Amazon River) is 7,050,000 km2 in area (or about 2,500,000 miles2), and covers about 40% of South America. Of this area, approximately 5,000,000 km2 is (or was) covered by high tropical rainforest, with the remainder covered by savannah ("campo") or scrubby woodland ("cerrado"). The Amazon basin covers significant portions of the countries of Brazil, Peru, Colombia, Ecuador, Venezuela and Bolivia, though the major part of the watershed lies within Brazil.

The next largest tropical watershed, that of the Congo River, at 3,690,000 km2, is only half the size of the Amazon basin. Violent Revolution Rocks South America! Although it now empties into the Atlantic Ocean, the Amazon once flowed into the Pacific! The uplift of the Andes Mountains about 65 million years ago in a geological event called the Laramide Revolution cut the flow to the Pacific, and forced the Amazon River to flow eastward. This revolution took place when the westward-moving South American (geological or tectonic) plate crashed headlong into the eastern-moving Nazca Plate. The Nazca plate was forced beneath the South American plate, lifting up the Andes mountains in a process that continues to this day, as evidenced by the many earthquakes and high volcanic activity of the Andes region. But It's a Dry Heat... The Amazon basin has not always been an area of lush tropical rainforest. At several times during its history, the basin has been the location of huge lakes and shallow seas.

Salt deposits up to 600 meters thick (nearly 2000 feet!) have also been found in some locations, indicating that at one time, the basin may have been desert-like, drying up the shallow seas and creating the salt deposits. A Well Watered Desert! Would you believe that the Amazon River has its own sand dunes? Echogrammes of the river bed below the mouth of the Rio Negro show giant sand dunes as long as 600 meters (2000 feet) and up to 12 meters (39 feet) in height. These dunes are gradually moved downstream in the same manner that wind moves sand-dunes in "true" deserts! A Bouillabaisse of Fishes. The Amazon basin is home to over 2,500 species of fish, more species than are recorded for the entire Atlantic Ocean, and some experts estimate that there may be as many as 6,000 species!

These range from giant 3-meter air-breathing fish (Arapaima gigas) and river catfish weighing up to 600-700 lbs, to tiny tetras, electric eels, sting-rays, needlefish, fresh-water flying-fish, and knife-fish. The fish fauna of many river systems is poorly known, and new species are discovered yearly, even in the "better-known" areas! Many of the above "Amazon Facts" are adapted from the following sources: The Amazon. Limnology and Landscape Ecology of a Mighty Tropical River and its Basin. (1984) H. Sioli, editor. Dr. W. Junk Publishers, Dordrecht (ISBN 90-6193-108-8). The Palms of the Amazon. (1995) A. Henderson. Oxford University Press, Oxford, 362 pages. (ISBN 0-19-508311-3). Field Guide to the Palms of the Americas (1995; A. Henderson, G. Galeano and R.

Bernal; Princeton University Press, Princeton, New Jersey; ISBN 0-691-08537-4) A Neotropical Companion. 2nd Ed. (1997) J. C. Kricher. Princeton University Press, Princeton, New Jersey, 451 pages. (ISBN 0-691-04433-3 See the Recommended Reading page for many more great sources of information. Learn About the Six Amazon River Basin Countries Share By Amanda Briney The Amazon River is the second longest river (it is just shorter than the Nile River in Egypt ) in the world and it has the largest watershed or drainage basin as well as the most tributaries of any river in the world. For reference, a watershed is defined as the area of land that releases its water into a river. This entire area is often referred to as the Amazon Basin. The Amazon River begins with streams in the Andes Mountains in Peru and flows into the Atlantic Ocean about 4,000 miles (6,437 km) away.

The Amazon River and its watershed encompass an area of 2,720,000 square miles (7,050,000 sq km). This area includes the largest tropical rainforest in the world - the Amazon Rainforest . In addition parts of the Amazon Basin also include grassland and savannah landscapes. As a result, this area is some of the least developed and most biodiverse in the world. Along its length, the Amazon River flows through three countries and its basin includes three more. continue reading below our video Test Your General Science Knowledge The following is a list of these six countries that have claims to the Amazon region arranged by their area. For reference, their capitals and populations have also been included. All information was obtained from the CIA World Factbook . • Area: 3,287,612 square miles (8,514,877 sq km) • Capital: Brasilia The Amazon Rainforest THE AMAZON RAINFOREST By Rhett Butler | Last updated 2016-Jan-23 The Amazon River Basin is home to the largest rainforest on Earth.

The basin -- roughly the size of the forty-eight contiguous United States -- covers some 40 percent of the South American continent and includes parts of eight South American countries: Brazil , Bolivia , Peru , Ecuador , Colombia , Venezuela , Guyana , and Suriname , as well as French Guiana , a department of France. Reflecting environmental conditions as well as past human influence , the Amazon is made up of a mosaic of ecosystems and vegetation types including rainforests, seasonal forests, deciduous forests, flooded forests , and savannas . The basin is drained by the Amazon River, the world's largest river in terms of discharge, and the second longest river in the world after the Nile. The river is made up of over 1,100 tributaries, 17 of which are longer than 1000 miles, and two of which (the Negro and the Madeira) are larger, in terms of volume, than the Congo (formerly the Zaire) river. The river system is the lifeline of the forest and its history plays an important part in the development of its rainforests. HISTORY 3. Indonesian Archipelago, Southeast Asia How large is the Amazon rainforest?

The extent of the Amazon depends on the definition. The the Amazon River drains about 6.915 million sq km (2.722 sq mi), or roughly 40 percent of South America, but generally areas outside the basin are included when people speak about "the Amazon." The biogeographic Amazon ranges from 7.76-8.24 million sq km (3-3.2 million sq mi), of which just over 80 percent is forested. For comparison, the land area of the United States (including Alaska and Hawaii) is 9,629,091 square kilometers (3,717,811 sq km). Nearly two-thirds of the Amazon lies in Brazil. At one time Amazon River flowed westward , perhaps as part of a proto-Congo (Zaire) river system from the interior of present day Africa when the continents were joined as part of Gondwana. Fifteen million years ago, the Andes were formed by the collision of the South American plate with the Nazca plate. The rise of the Andes and the linkage of the Brazilian and Guyana bedrock shields, blocked the river and caused the Amazon to become a vast inland sea.

Gradually this inland sea became a massive swampy, freshwater lake and the marine inhabitants adapted to life in freshwater. For example, over 20 species of stingray , most closely related to those found in the Pacific Ocean, can be found today in the freshwaters of the Amazon. About ten million years ago, waters worked through the sandstone to the west and the Amazon began to flow eastward. At this time the Amazon rainforest was born. During the Ice Age, sea levels dropped and the great Amazon lake rapidly drained and became a river. Three million years later, the ocean level receded enough to expose the Central American isthmus and allow mass migration of mammal species between the Americas. The Ice Ages caused tropical rainforest around the world to retreat. Although debated , it is believed that much of the Amazon reverted to savanna and montane forest (see chapter 3-Ice Ages and Glaciation). Savanna divided patches of rainforest into "islands" and separated existing species for periods long enough to allow genetic differentiation (a similar rainforest retreat took place in Africa. Delta core samples suggest that even the mighty Congo watershed was void of rainforest at this time).

When the ice ages ended, the forest was again joined and the species that were once one had diverged significantly enough to be constitute designation as separate species, adding to the tremendous diversity of the region. About 6000 years ago, sea levels rose about 130 meters, once again causing the river to be inundated like a long, giant freshwater lake. THE AMAZON RIVER TODAY Today the Amazon River is the most voluminous river on Earth, eleven times the volume of the Mississippi, and drains an area equivalent in size to the United States. During the high water season, the river's mouth may be 300 miles wide and every day up to 500 billion cubic feet of water (5,787,037 cubic feet/sec) flow into the Atlantic. For reference, the Amazon's daily freshwater discharge into the Atlantic is enough to supply New York City's freshwater needs for nine years. The force of the current -- from sheer water volume alone -- causes Amazon River water to continue flowing 125 miles out to sea before mixing with Atlantic salt water. Early sailors could drink freshwater out of the ocean before sighting the South American continent.

The river current carries tons of suspended sediment all the way from the Andes and gives the river a characteristic muddy whitewater appearance. It is calculated that 106 million cubic feet of suspended sediment are swept into the ocean each day. The result from the silt deposited at the mouth of the Amazon is Majaro island, a river island about the size of Switzerland. THE AMAZON RAINFOREST While the Amazon Basin is home to the world's largest tropical rainforest, the region consists of a number of ecosystems ranging from natural savanna to swamps. Even the rainforest itself is highly variable, tree diversity and structure varying depending on soil type, history, drainage, elevation, and other factors. This is discussed at greater length in the rainforest ecology section . THE CHANGING AMAZON RAINFOREST The Fate of the Forest by Susanna Hecht and Alexander Cockburn The Amazon has a long history of human settlement, but in recent decades the pace of change has accelerated due to an increase in human population, the introduction of mechanized agriculture, and integration of the Amazon region into the global economy.

Vast quantities of commodities produced in the Amazon — cattle beef and leather, timber, soy, oil and gas, and minerals, to name a few — are exported today to China, Europe, the U.S., and other countries. This shift has had substantial impacts on the Amazon. This transition from a remote backwater to a cog in the global economy has resulted in large-scale deforestation and forest degradation in the Amazon — more than 1.4 million hectares of forest have been cleared since the 1970s. An even larger area has been affected by selective logging and forest fires. Conversion for cattle grazing is the biggest single direct driver of deforestation. In Brazil, more than 60 percent of cleared land ends up as pasture, most of which has low productivity, supporting less than one head per hectare. Across much of the Amazon, the primary objective for cattle ranching is to establish land claims, rather than produce beef or leather. But market-oriented cattle production has nonetheless expanded rapidly during the past decade. Industrial agricultural production , especially soy farms, has also been an important driver of deforestation since the early 1990s.

However since 2006 the Brazil soy industry has had a moratorium on new forest clearing for soy. The moratorium was a direct result of a Greenpeace campaign . Mining, subsistence agriculture, dams, urban expansion, agricultural fires, and timber plantations also result in significant forest loss in the Amazon. Logging is the primary driver of forest disturbance and studies have shown that logged-over forests — even when selectively harvested — have a much higher likelihood of eventual deforestation. Logging roads grant access to farmers and ranchers to previous inaccessible forest areas. Deforestation isn't the only reason the Amazon is changing. Global climate change is having major impacts on the Amazon rainforest. Higher temperatures in the tropical Atlantic reduce rainfall across large extents of the Amazon, causing drought and increasing the susceptibility of the rainforest to fire. Computer models suggest that if current rates of warming continue, much of the Amazon could transition from rainforest to savanna, especially in the southern parts of the region. Such a shift could have dramatic economic and ecological impacts, including affecting rainfall that currently feeds regions that generate 70 percent of South America's GDP and triggering enormous carbon emissions from forest die-off. These emissions could further worsen climate change.

PROTECTING THE AMAZON RAINFOREST While destruction of the Amazon rainforest is ongoing, the overall rate of deforestation rate in the region is slowing, mostly due to to the sharp drop in forest clearing in Brazil since 2004. Brazil's declining deforestation rate has been attributed to several factors, some of which it controls, some of which it doesn't. Since 2000 Brazil has established the world's largest network of protected areas, the majority of which are located in the Amazon region. Since 2004 the government has also had a deforestation reduction program in place. This includes improved law enforcement, satellite monitoring, and financial incentives for respecting environmental laws. Furthermore, the private sector — especially the soy, logging, and cattle industries — are increasingly responsive to consumer demand for less-damaging commodities. Finally the Brazilian Amazon has been the site of a number of innovative and ambitious conservation experiments, ranging from jurisdictional commodity certification to indigenous led Reducing Emissions from Deforestation and Degradation (REDD+) projects to Norway's billion dollar performance-based payment for cutting deforestation.

AMAZON RAINFOREST PICTURE HIGHLIGHTS Amazon River | Facts, History, Animals, & Map | Britannica.com Amazon River Leticia Amazon River, Portuguese Rio Amazonas, Spanish Río Amazonas, also called Río Marañón and Rio Solimões, the greatest river of South America and the largest drainage system in the world in terms of the volume of its flow and the area of its basin . The total length of the river—as measured from the headwaters of the Ucayali - Apurímac river system in southern Peru —is at least 4,000 miles (6,400 km), which makes it slightly shorter than the Nile River but still the equivalent of the distance from New York City to Rome . Its westernmost source is high in the Andes Mountains , within 100 miles (160 km) of the Pacific Ocean , and its mouth is in the Atlantic Ocean , on the northeastern coast of Brazil . However, both the length of the Amazon and its ultimate source have been subjects of debate since the mid-20th century, and there are those who claim that the Amazon is actually longer than the Nile.

(See below The length of the Amazon .) Streams of the Andes Mountains converge, eventually forming the Amazon River. Encyclopædia Britannica, Inc. Aerial view of the Amazon River in Brazil. © guentermanaus/Shutterstock.com The vast Amazon basin (Amazonia), the largest lowland in Latin America , has an area of about 2.7 million square miles (7 million square km) and is nearly twice as large as that of the Congo River , the Earth ’s other great equatorial drainage system. Stretching some 1,725 miles (2,780 km) from north to south at its widest point, the basin includes the greater part of Brazil and Peru , significant parts of Colombia , Ecuador , and Bolivia , and a small area of Venezuela ; roughly two-thirds of the Amazon’s main stream and by far the largest portion of its basin are within Brazil. The Tocantins-Araguaia catchment area in Pará state covers another 300,000 square miles (777,000 square km). Although considered a part of Amazonia by the Brazilian government and in popular usage, it is technically a separate system.

It is estimated that about one-fifth of all the water that runs off the Earth’s surface is carried by the Amazon. The flood-stage discharge at the river’s mouth is four times that of the Congo and more than 10 times the amount carried by the Mississippi River . This immense volume of fresh water dilutes the ocean’s saltiness for more than 100 miles (160 km) from shore. The Central and Northern Andes and the Amazon River basin and drainage network. Encyclopædia Britannica, Inc. The size of the Amazon River basin in relation to the U.S. state of Texas. Encyclopædia Britannica, Inc. Paraguay River The extensive lowland areas bordering the main river and its tributaries, called várzeas (“floodplains”), are subject to annual flooding, with consequent soil enrichment; however, most of the vast basin consists of upland, well above the inundations and known as terra firme . More than two-thirds of the basin is covered by an immense rainforest, which grades into dry forest and savanna on the higher northern and southern margins and into montane forest in the Andes to the west.

The Amazon Rainforest , which represents about half of the Earth’s remaining rainforest, also constitutes its single largest reserve of biological resources. Since the later decades of the 20th century, the Amazon basin has attracted international attention because human activities have increasingly threatened the equilibrium of the forest’s highly complex ecology. Deforestation has accelerated, especially south of the Amazon River and on the piedmont outwash of the Andes, as new highways and air transport facilities have opened the basin to a tidal wave of settlers, corporations, and researchers. Significant mineral discoveries have brought further influxes of population. The ecological consequences of such developments, potentially reaching well beyond the basin and even gaining worldwide importance, have attracted considerable scientific attention (see Sidebar: Status of the World’s Tropical Forests ). Exploring Latin American History The first European to explore the Amazon, in 1541, was the Spanish soldier Francisco de Orellana , who gave the river its name after reporting pitched battles with tribes of female warriors, whom he likened to the Amazons of Greek mythology . Although the name Amazon is conventionally employed for the entire river, in Peruvian and Brazilian nomenclature it properly is applied only to sections of it.

In Peru the upper main stream (fed by numerous tributaries flowing from sources in the Andes) down to the confluence with the Ucayali River is called Marañón , and from there to the Brazilian border it is called Amazonas. In Brazil the name of the river that flows from Peru to its confluence with the Negro River is Solimões ; from the Negro out to the Atlantic the river is called Amazonas. False-colour satellite image of the confluence of the silt-laden Solimões River (bottom) … David Skole, Michigan State University/NASA Landsat Pathfinder EU Considers Rules For Robots The length of the Amazon The debate over the location of the true source of the Amazon and over the river’s precise length sharpened during the second half of the 20th century, as technological advances made it possible to explore deeper into the extremely remote locations of the Amazon’s headstreams and to more accurately measure stream lengths. Beginning in the 1950s, explorers of the region cited various mountains in Peru as possible sources, but they did so without taking precise measurements or applying hydrological research.

An expedition in 1971, sponsored by the National Geographic Society , pinpointed Carruhasanta Creek, which runs off the north slope of Mount Mismi in southern Peru, as the source of the river. This location became widely accepted in the scientific community and remained so until the mid-1990s—although a Polish expedition in 1983 contended that the source of the river was actually another stream, nearby Apacheta Creek . (The Carruhasanta and Apacheta streams form the Lloqueta River, an extension of the Apurímac .) With the introduction of Global Positioning System (GPS) technology in the 1990s, researchers again attempted to navigate the entire length of the Amazon. The American geographer Andrew Johnston of the Smithsonian Institution ’s Air and Space Museum in Washington, D.C. , employed GPS gear to explore the various Andean rivers that flow into the Amazon. Using the definition of the river’s source as being the farthest point from which water could flow into the ocean and where that water flows year-round (thereby eliminating those rivers that freeze in winter), he concluded that the source was Carruhasanta Creek on Mount Mismi.

Connect with Britannica Facebook Twitter YouTube Instagram Pinterest By the early 21st century, advanced satellite-imagery technology was allowing researchers to match the river’s dimensions even more precisely. In 2007 an expedition that included members of Brazil’s National Institute for Space Research and other organizations traveled to the region of Carruhasanta and Apacheta creeks in an attempt to determine which of the two was the “true” source of the Amazon. Their data revealed that Apacheta was 6 miles (10 km) longer than Carruhasanta and carries water year-round, and they concluded that Apacheta Creek was indeed the source of the Amazon River. The team then proceeded to measure the river’s length. As part of this process, they had to determine from which of the Amazon’s three main outlets to the sea to begin the measurement—the Northern or Southern channels, which flow north of Marajó Island , or Breves Channel, which flows southward around the western edge of the island to join the Pará River estuary along the southern coast of the island.

They chose to use the southern channel and estuary , since that constituted the longest distance from the source of the river to the ocean (at Marajó Bay); according to their calculations, the southern outlet lengthened the river by 219 miles (353 km). Their final measurement for the length of the Amazon—from Apacheta Creek to the mouth of Marajó Bay—was about 4,345 miles (6,992 km). This team of researchers, using the same technology and methodology , then measured the length of the Nile River , which they determined to be about 4,258 miles (6,853 km); that value was some 125 miles (200 km) longer than previous calculations for the Nile but nearly 90 miles (145 km) shorter than the length the group gave for the Amazon. These measurements infer that the Amazon may be recognized as the world’s longest river, supplanting the Nile. However, a river like the Amazon has a highly complex and variable streambed—made more so by seasonal climatic factors—which complicates the process of obtaining an accurate measurement.

Thus, the final length of the river remains open to interpretation and continued debate. Editor Picks: Exploring 10 Types of Basketball Movies The Amazon basin is a great structural depression, a subsidence trough that has been filling with immense quantities of sediment of Cenozoic age (i.e., dating from about the past 65 million years). This depression, which flares out to its greatest dimension in the Amazon’s upper reaches, lies between two old and relatively low crystalline plateaus, the rugged Guiana Highlands to the north and the lower Brazilian Highlands (lying somewhat farther from the main river) to the south. The Amazon basin was occupied by a great freshwater sea during the Pliocene Epoch (5.3 to 2.6 million years ago). Sometime during the Pleistocene Epoch (about 2,600,000 to 11,700 years ago) an outlet to the Atlantic was established, and the great river and its tributaries became deeply entrenched in the former Pliocene seafloor. The modern Amazon and its tributaries occupy a vast system of drowned valleys that have been filled with alluvium .

With the rise in sea level that followed the melting of the Pleistocene glaciers, the steep-sided canyons that had been eroded into the Pliocene surface during the period of lower sea levels were gradually flooded. In the upper part of the basin—in eastern Colombia , Ecuador , Peru, and Bolivia —more-recent outwash from the Andes has covered many of the older surfaces. Page 1 of 8 Unique Facts About South & Central America: : The Amazon River Unique Facts- South America The Amazon River The Amazon River (occasionally River Amazon; Spanish: Río Amazonas, Portuguese: Rio Amazonas) of South America is one of the longest two rivers on Earth, the Nile River in Africa being the other. The Amazon has by far the greatest total flow of any river, carrying more than the Mississippi, Nile, and Yangtze rivers combined. It also has the largest drainage area of any river system. It may be correctly stated that the Nile is the longest river, while the Amazon is the strongest. The quantity of fresh water released to the Atlantic Ocean is enormous: 184,000 m³ per second (6.5 million ft³/s) in the rainy season.

Indeed, the Amazon is responsible for a fifth of the total volume of fresh water entering the oceans worldwide. It is said that offshore of the mouth of the Amazon potable water can be drawn from the ocean while still out of sight of the coastline, and the salinity of the ocean is notably lower a hundred miles out to sea. The main river (which is usually between one and six miles wide) is navigable for large ocean steamers to Manaus. Smaller ocean vessels of 3,000 tons and 5.5 m (18 ft) draft can reach as far as Iquitos, 3,700 km (2,300 miles) from the sea. Smaller riverboats can reach 780 km (486 mi) higher as far as Achual Point. Beyond that, small boats frequently ascend to the Pongo de Manseriche, just above Achual Point. Mouth of the Amazon seen from space, looking south.(Photo courtesy of NASA) The Amazon drains an area of some 6,915,000km² (2,722,000 mile²), or some 40 percent of South America.

It gathers its waters from 5 degrees north latitude to 20 degrees south latitude. Its most remote sources are found on the inter-Andean plateau, just a short distance from the Pacific Ocean; and, after a course of about 7,200 km (4,800 mi) through the interior of Peru and across Brazil, it enters the Atlantic Ocean at the equator. The ultimate source of the Amazon has only recently been firmly established as a stream on a 5,597 metre (18,363 ft) peak called Nevado Mismi in the Peruvian Andes, roughly 160 km (100 miles) N.N.E. of Lima. The mountain was first suggested as the source in 1971 but this was not confirmed until 2001. The stream from Nevado Mismi flows into Lake Lauricocha and then the Apurímac River. The Apurímac is a tributary of the Ucayali, which joins the Marañón to form the Amazon proper. Below its confluence with the Huallaga, the river leaves Andean terrain and is instead surrounded by flood plain.

From this point to the Ucayali, some 2,400 km (1,500 mi), the forested banks are just out of water, and are inundated long before the river attains its maximum flood-line. The low river banks are interrupted by only a few hills, and the river enters the enormous Amazon Rainforest. Seasonal rains give rise to extensive floods along the course of the Amazon and its tributaries. The average depth of the river in the height of the rainy season is 40 m (120 ft) and the average width can be nearly twenty-five miles. It starts to rise in November, and increases in volume until June, then falls until the end of October. The rise of the Negro branch is not synchronous; the rainy season does not commence in its valley until February or March. By June it is full, and then it begins to fall with the Amazon. The Madeira rises and falls two months earlier than the Amazon. Manaus, the largest city on the Amazon, as seen from a NASA satellite image, surrounded by the muddy Amazon River and the dark Negro River.

The abundance of water in the Amazon basin is due to the fact that much of this lies in the region below the Intertropical convergence zone, where rainfall is at a maximum. Also, the basin lies in the Trade Wind zone, where moisture from the Atlantic is pushed westwards, and eventually forced to rise over the Andes, the second tallest mountain range on Earth, where the moist air cools and precipitates water. This combination creates more rainfall over a large river basin than anywhere else on the planet. In the rainy season, the Amazon inundates the country throughout its course to the extent of several hundred thousand square miles, covering the flood-plain, called vargem. The flood-levels are, in some places, from 12 to 15 m (40 to 50 ft) higher than levels during the dry season. During the flood, the level at Iquitos is 6 m (20 ft); at Teffe, it is 15 m (45 ft); near Obidos, 11 m (35 ft); and at Para, 4 m (12 ft), above the low-water extreme seen during the dry season.

Before the conquest of South America, the Río de las Amazonas had no general name; instead, indigenous peoples had names for the sections of the river they occupied, such as Paranaguazu, Guyerma, Solimões and others. In the year 1500, Vicente Yañez Pinzon, in command of a Spanish expedition, became the first European to explore the river, exploring its mouth when he discovered that the ocean off the shore was fresh water. Pinzon called the river the Rio Santa Maria de la Mar Dulce, which soon became abbreviated to Mar Dulce, and for some years, after 1502, it was known as the Rio Grande. Pinzon's companions called the river El Río Marañón. The word Marañón is thought by some to be of indigenous origin. This idea was first stated in a letter from Peter Martyr to Lope Hurtado de Mendoza in 1513.

However, the word may also be derived from the Spanish word "maraña" — meaning a tangle, a snarl, which well represents the bewildering difficulties which the earlier explorers met in navigating not only the entrance to the Amazon, but the whole island-bordered, river-cut and indented coast of what is now the Brazilian state of Maranhão. The name Amazon arises from a battle which Francisco de Orellana had with a tribe of Tapuyas where the women of the tribe fought alongside the men, as was the custom among the entire tribe. Orellana derived the name Amazonas from the ancient Amazons of Asia and Africa described by Herodotus and Diodorus. Four centuries after the discovery of the Amazon river, the total cultivated area in its basin was probably less than 25 square miles (65 km²), excluding the limited and rudely cultivated areas among the mountains at its extreme headwaters. This situation changed dramatically during the 20th century. Wary of foreign exploitation of the nation's resources, Brazilian governments in the 1940s set out to develop the interior, away from the seaboard where foreigners owned large tracts of land.

The original architect of this expansion was President Getúlio Vargas, the demand for rubber from the Allied forces in World War II providing funding for the drive. Amazon River Interior (photo courtesy NASA Goddard Space Flight Center's Laboratory for Terrestrial Physics) The construction of the new capital Brasilia in the interior in 1960 also contributed to the opening up of the Amazon basin. A large scale colonization program saw families from north-eastern Brazil relocated to the forests, encouraged by promises of cheap land. Many settlements grew along the road from Brasilia to Belem, but rainforest soil proved difficult to cultivate. Still, long-term development plans continued. Roads were cut through the forests, and in 1970, the work on Trans-Amazon highway network began. The network's three pioneering highways were completed within ten years, connecting all the major cities of the Brazilian Amazon interior. Cattle farming became a major impetus in deforestation, with military governments in the 1960s and 1970s heavily subsidising the creation of large ranches.

By the 1980s the rate of destruction of the rainforest was dizzying, and it is estimated that over a fifth of the total area of the rainforest has now been clearcut. The preservation of the remaining forest is becoming an ever more prominent concern. Brazil Brazil Official name : Federative Republic of Brazil Area: 8,511,965 square kilometers (3,286,488 square miles) Highest point on mainland: Neblina Peak (Pico da Neblina) (3,014 meters/9,888 feet) Lowest point on land: Sea level Hemispheres: Southern, Northern, and Western Time zone: There are four time zones. From east to west—noon GMT = 10 A.M. on the Fernando de Noronha islands; 9 A.M. in Rio de Janeiro; 8 A.M. A.M.

in Rio Branco (westernmost) Longest distances: 4,328 kilometers (2,689 miles) from north to south; 4,320 kilometers (2,684 miles) east to west Land boundaries: Total: 14,691 kilometers (9,108 miles); Argentina, 1,224 kilometers (759 miles); Bolivia, 3,400 kilometers (2,108 miles); Colombia, 1,643 kilometers (1,019 miles); French Guiana, 673 kilometers (417 miles); Guyana, 1,119 kilometers (694 miles); Paraguay, 1,290 kilometers (800 miles); Peru, 1,560 kilometers (967 miles); Suriname, 597 kilometers (307 miles); Uruguay, 985 kilometers (612 miles); Venezuela, 2,200 kilometers (1,364 miles) Coastline: 7,491 kilometers (4,655 miles) Territorial sea limits: 22 kilometers (1

2 nautical miles) 1 LOCATION AND SIZE Brazil is the largest country in South America and shares common boundaries with every South American country except Chile and Ecuador.

Its eastern coastline borders the Atlantic Ocean. With an area of 8,511,965 square kilometers (3,286,488 square miles), it is slightly smaller than the United States. The country is divided into twenty-six states and one federal district. Brazil has land area in both the Northern and Southern Hemispheres, because the equator crosses through the northern part of the country. 2 TERRITORIES AND DEPENDENCIES Brazil designates the Fernando de Noronha Islands (Arquipelago de Fernando de Noronha), which lie off its northeast coast, as a territory. The country also controls several small islands in the Atlantic Ocean. 3 CLIMATE Brazil's geographical diversity makes for a range of climatic conditions. Most of the country has a tropical climate. The southernmost regions lie outside the tropics and have a temperate climate. May through September are the coolest months, and the higher elevations in the south may receive snow during this time. In the north, the coastal areas experience tropical conditions, while the upland interior is relatively dry and moderate. Rainfall varies widely across the country.

In the southern and central part of the country, it generally ranges between 150 centimeters to 200 centimeters (58 inches to 78 inches) annually, but it can be much higher in certain areas. Rainfall is heavier in the Amazon River basin, reaching as much as 300 centimeters (117 inches) annually. Parts of this region experience dry spells of three months or more each year. The northeast region is the driest and hottest part of the country, with lengthy droughts a regular occurrence. S 17°C (63°F) 4 TOPOGRAPHIC REGIONS The Amazon River basin and its many tributaries dominate the northern part of Brazil, occupying two-fifths of the country. The Guiana Highlands, home to the country's highest point, Neblina Peak (Pico da Neblina) near the Venezuela border, are in the northernmost part of the Amazon River basin. To the south is a large plateau called the Brazilian Highlands. This plateau meets the Atlantic Ocean in a steep wall-like slope called the Great Escarpment. The highland block of the country is part of the South American Tectonic Plate.

5 OCEANS AND SEAS Seacoast and Undersea Features Brazil's eastern seaboard borders the Atlantic Ocean, with a continental shelf that extends some 370 kilometers (200 nautical miles). The waters of the continental shelf are extremely shallow. Reefs and sandbars dot the shoreline. Sea Inlets and Straits Duck Lagoon (Lagoa dos Patos), on the southern coast of Brazil, is a long, shallow tidal lagoon separated from the Atlantic Ocean by a wide sandbar. It covers an area of 10,153 square kilometers (3,920 square miles) and is the largest lagoon in the world. Harbors in Brazil include, from south to north: Pôrto Alegre, in Rio Grande do Sul; Santos, in the port of São Paulo; Rio de Janeiro; Vitória, just north of Rio de Janeiro in Espírito Santo; and Belem and Macapá, both at the mouth of the Amazon River. Islands and Archipelagos Many islands exist throughout the river system and delta area of the Amazon. One of the world's largest riverine islands, Marajó, is the largest island in the Amazon River Delta.

(A riverine island is one situated in a river.) It lies in the center of the mouth of the Amazon River, separating the western arm from the eastern arm, known as the Pará River. Maracá Island lies north of the mouth of the Amazon, just to the south of Brazil's border with French Guiana. The Fernando de Noronha Islands are a group of volcanic islands off the northeastern bulge of the country. The island state of Santa Catarina is located off the nation's southern coast, between São Paulo and Pôrto Alegre. Coastal Features Brazil's beaches are among the most famous in the world, including Copacabana and Ipanema, found near Rio de Janeiro. Near the Uruguay border, a large sandbar separates Duck Lagoon from the Atlantic Ocean. 6 INLAND LAKES Brazil has several small lakes throughout the Amazon River basin that formed naturally through flooding of the river systems.

The largest of Brazil's natural lakes is the Duck Lagoon; the other large lakes are artificial, such as Sobradinho (3,970 square kilometers/ 1,533 square miles); Tucuruí (2,820 square kilometers/1,089 square miles); Balbina (2,360 square kilometers/911 square miles); and Serra da Mesa (1,784 square kilometers/689 square miles). DID YOU KNOW? Tropical climate is typically hot and humid, with both abundant rainfall and intense sunshine; the main difference between seasons is the amount of rainfall. Temperate climate is generally mild, with greater differences in temperature from season to season. 7 RIVERS AND WATERFALLS The Amazon River is Brazil's longest river and the second-longest river in the world. It covers 3,218 kilometers (2,000 miles) within the country of Brazil, but it has a total length of about 6,570 kilometers (4,080 miles). It starts in Peru and flows through Colombia and Brazil before reaching the Atlantic Ocean.

The Amazon has eighteen major tributaries, including ten that carry more water than the Mississippi River. The river is also known as having the world's largest flow of water, with about 303 million liters (80 million gallons) of water per second emptying into the Atlantic Ocean. The Amazon River basin contains the world's largest tropical rain forest, which provides a natural replacement for 15 percent or more of the world's oxygen in the atmosphere. The number of species in this forest is unknown, but about one-fourth of the world's known plant species can be found in Brazil. Along much of the river in the Amazon basin, there are stretches of varzea (flat, swampy land) that is subject to frequent flooding and is underwater for part of every year. The São Francisco River is the longest river contained entirely in Brazil. It starts near Belo Horizonte and flows northeastward along a line parallel to the coast before turning eastward toward the sea. At the border between the states of Sergipe and Alagoas, it drops 80 meters (265 feet) through a series of three spectacular waterfalls.

The falls, known as Paulo Afonso Falls, lie about 305 kilometers (190 miles) from the mouth of the river on the Atlantic coast. The Río de la Plata basin in the south includes three major rivers: Paraná, Uruguay, and Paraguay. The upper reaches of the Paraguay River contain a wet lowland system in western Mato Grosso called the Pantanal. Part of the region is protected as the Pantanal National Park, made up of swamp and marshland and supporting diverse wildlife. The Pantanal covers an area of about 140,000 square kilo-meters (50,000 square miles) and is part of the world's largest freshwater wetland system. The magnificent Iguazú Falls are located on the Iguazú River near the border with Argentina. The Iguazú River starts near the city of Curitaba and flows into the Paraná River. The Iguazú Falls include about 275 individual cataracts in a complex system that is 4.8 kilometers (3 miles) wide and 82 meters (270 feet) high.

8 DESERTS There are no desert regions in Brazil, although the northeast is arid, with dunes of white sand. Concern about desertification, the process where arid land becomes desert, is raised during periods of drought, but when the rains are normal, lagoons form between the dunes. 9 FLAT AND ROLLING TERRAIN Grasslands cover major portions of the south and west-central regions. The plains of Rio Grande do Sul, the southernmost state of Brazil, are called pampas and provide fields for cattle raising. The southern part of the west-central region is a rolling prairie with rivers draining southward. Its soils are particularly suited for agriculture. The northern, western, and central areas of the Central Highlands (Brazilian Highlands) feature broad, rolling terrain with low, rounded hills. Names have been given to some systems of hills, but these hills do not reach altitudes high enough to be considered mountains. 10 MOUNTAINS AND VOLCANOES With an elevation of 3,014 meters (9,888 feet), the Neblina Peak (Pico da Neblina) in the Imeri range is Brazil's highest peak.

It is located in the Guiana Highlands near the border with Venezuela. The Serra do Mar runs along the coast for 1,609 kilometers (1,000 miles) from Santa Catarina to Rio de Janeiro and northward to join the Serra dos Orgaos. This extended range has an average height of about 1,524 meters (5,000 feet) topped by peaks above 2,133 meters (7,000 feet), including Pedra Acu, which rises to 2,318 meters (7,605 feet) just west of Rio de Janeiro. The Serra do Mar is so near the tidewater in many places that it rises almost directly from the shore. The Serra da Mantiqueira is the highest and most rugged range of the Central Highlands. It includes the Bandeira Peak (Pico da Bandeira), which at 2,890 meters (9,482 feet) is the highest elevation in the Central Highlands.

The Serra do Espinhaço, or "Backbone Mountains," form a type of spine that determines the drainage divide between the São Francisco River to the west and short streams that tumble eastward to the Atlantic Ocean. It contains a great wealth of minerals. Sometimes the Serra do Espinhaço and the Serra da Mantiqueira are referred to collectively as the Serra Geral. 11 CANYONS AND CAVES There are no significant caves or canyons in Brazil. 12 PLATEAUS AND MONOLITHS The Central Highlands are often called the Brazilian Highlands or Brazilian Plateau. The region covers nearly all of Brazil south of the Amazon River basin. The Guiana Highlands form part of an immense plateau that reaches higher altitudes than the Central Highlands. The Guiana Highlands extend into Venezuela, Guyana, Suriname, and French Guiana. 13 MAN-MADE FEATURES Most of Brazil's energy comes from the hydroelectric power created by dams. The Sete Quedas hydroelectric power project is located on the Paraná River. The Tucuruí Dam created Lake Tucuruí, near the mouth of the Amazon River.

It was the first large dam ever built in a tropical rainforest and has created one of the largest man-made lakes to exist in such a region. The Sobradinho Dam created Lake Sobradinho along the São Francisco River. The Itaipú Hydroelectric Power Station created the Itaipu Reservoir, located near Iguazú Falls. 14 FURTHER READING Burns, E. Bradford. A History of Brazil . 3rd ed. New York: Columbia University Press, 1993. Haverstock, Nathan A. Brazil in Pictures . Minneapolis: Lerner, 1987. Munro, David. The Oxford Dictionary of the World . New York: Oxford University Press, 1995. Periodicals Van Dyk, Jere. "The Amazon." National Geographic , February 1995, pp. 2-39. Web Sites

Question: The main mouth of the Amazon lies in which country?
Answer: Brazil