Amazon River Basin

As a drainage basin, the Amazon covers more than 7 million square kilometers in South America, making it the largest in the world. The Amazon basin encompasses portions of Bolivia, Brazil, Colombia, Ecuador, Suriname, Peru, and Venezuela, and roughly two thirds of this area fall within Brazil. Many of the main rivers of the basin are more than 2 kilometers wide, and the Amazon itself discharges roughly 175,000 m3 of water per second into the Atlantic.

Climate in the Amazon is eminently tropical with limited variation in temperatures and more seasonal variability in rainfall, which is generally greater from November to May. Soils in the Amazon were once believed to be very fertile, but most of the basin has relatively old, weathered soils that are nutrient-poor ...