AMAZING FACTS ABOUT THE AMAZON BASIN
The Amazon basin has the most developed rainforest of anywhere in the world. Over two-thirds of all the fresh water on earth is found within the Amazon basin and over 20% of the earth’s oxygen is produced there. Although exact numbers are not known, the basin may contain up to one million plant species. The Amazon basin is drained by the Amazon River and its thousands of tributaries. The basin covers an area of approximately 2.5 million square miles (650 million hectares) which is approximately 40% of South America. If superimposed on the United States, it would cover nearly all of the contiguous 48 states!
The headwaters of the Amazon River are in the Andes Mountains of Peru and a mere 120 miles (190 km) from the Pacific Ocean. From there the River stretches eastward for approximately 4,000 miles (6,400 km) until if finally empties into the Atlantic Ocean at Belém in Brazil. Over this 4,000-mile length no bridge crosses the Amazon. There are approximately 1,100 tributaries that service the main river, seventeen of which are over 1,000 miles (1600 kilometers) long; the Río Negro is the most dominant tributary.
The tributaries vary in color from cloudy yellow, to clear black depending on the soil and vegetative environment of the area they are flowing from. Seasonal flooding brings soil and minerals from the mountains to the flood plains along the river, enriching the nutrient poor soil. The water level in the Amazon River can fluctuate by as much as 40 feet (12 m). The lowest levels occur in the months of August to September, and the highest levels occur in April and May. When the water is at its high point the River can be as wide as 300 miles (560 km), and at this time up to 500 billion cubic feet (14 billion m3) of water surge out to sea per day. Imagine… this is enough to sustain New York City’s fresh water supply for nine years!
The River’s deepest point occurs near the Atlantic Ocean where its depth is about 121 feet (37 m). The flow of the effluent into the Atlantic is so strong, that the waters of the Amazon River do not even begin to mix with the ocean water until the water has flowed 125 miles (230 km) into the Atlantic. This incredible force is generated purely by the sheer volume of water that flows, not by a seep gradient; indeed, the gradient from 2300 miles (3700 km) inland to where the Amazon meets the ocean would be barely enough to drain a bathtub!