The Amazon River

               The Amazon basin (or catchment) occupies approximately 7 million square kilometers in the North Central part of South America. Most of it is in Brazil, but it also includes parts of Bolivia, Colombia, Ecuador, Guyana, and small parts of French Guiana, Surinam and Venezuela.
               It is estimated that the Amazon discharges between 34 and 121 million liters of water per second and deposits a daily average of 3 million tons of sediment near its mouth. The outpouring of water and sediment is so vast that the salinity and colour of the Atlantic Ocean are altered for a distance of about 320 km from the mouth of the river.
               The major headstreams of the Amazon are the Ucayali and Maranón rivers, both of which rise in the permanent snows and glaciers of the high Andes Mountains and follow parallel courses north before joining near Nauta, Peru.
               The mouth of the main stream is 80 km (50 mi) wide. This branch, known as the Pará, is separated from a smaller branch by Marajó Island, which has an area of more than 36,000 sq km (14,000 sq mi).

The Amazon and its changeable Seasons

               The Amazon catchment includes the largest and wettest tropical plain in the world. Heavy rains drench much of the densely forested lowland region throughout the year but especially between January and June. In Brazil the width of the river ranges between 1.6 and 10 km (1 and 6 miles) at low water but expands to 48 km (30 miles) or more during the annual floods.
               The rate of flow ranges between 2.4 and 8 km/hr (1.5 and 5 mph); and the crest of the water at flood time often rises 15 m (50 ft) above normal. In one section near Óbidos, the bed is more than 91 metres (300 ft) below the average surface level of its water.
               Because of its size, annual floods, and navigability, the Amazon is often called the Ocean River. Transatlantic ships call regularly at Manaus, nearly 1,600 km upstream, and ships of 3,000 tons can reach Iquitos, Peru, 3,700 km from the river's mouth, the farthest point from sea of any port serving ocean traffic. River steamers of more modest tonnage can navigate on more than 100 of the larger tributaries

Amazonian Fauna

               No one really knows how many species there are in the Amazon forest, but scientists estimate that there are between 800,000 and 5 million species living there, amounting to 15 to 30 percent of all the species in the entire world. As naturalists catalogue new species of freshwater fish, their findings suggest that there may be as many as 3,000 kinds of fish in the Amazon's rivers and lakes.
               In main river channels and in larger lakes with plenty of food they generally leave swimmers unmolested. They appear to become aggressive only when they do not have enough nourishment.