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The Amazon river flows through several countries during its 6,400-kilometre journey across the continent of South America. Its waters are the lifeblood of the Amazon rainforest, which covers 40% of Brazil.
To ride the river through the rainforest is to be carried through a world of wonders. Around 430 types of mammals, 2.5 million insect varieties, 3,000 types of fish, and 1,300 types of birds (a third of the world's bird species are believed to dwell here) can be found along within and along it—not to mention the 40,000 or so plant species.
Where does the Amazon River begin and end?
The river originates high in the Andes mountains, a long mountain range that covers the western side of the continent. From there it flows east toward the Atlantic, spilling into the ocean with such force that the sea takes on the same brownish color as the river for a while before giving way to ocean blue. Ships approaching the mouth of the river will encounter this brownish water long before the coast of South America is in sight.
How was the river formed?
Millions of years ago, the Amazon actually flowed in the opposite direction, that being west into the Pacific Ocean. This was back when South America—together with Antarctica, Africa, Australia and India—formed part of a super-continent called Gondwanaland.
When this landmass began to split, South America drifted into the Pacific tectonic plate, bringing about a collision that formed the Andes Mountains. These mountains blocked the river's passage, creating freshwater lakes in the process.
The Amazon remained a lake rather than a river, until the movements of the earth allowed the water to break through the barriers and surge forth into the Atlantic Ocean, flooding all in its path and creating the river we know today.
Why does the Amazon rainforest have such a thriving ecosystem?
The soil of the Amazon Jungle is actually not particularly fertile. Any nutrients that reach the ground from the trees above are quickly recycled by the forest, either being reabsorbed by the roots of the trees, or broken down by fungi, termites worms and other decomposers that live on the forest floor.
Yet the rainforest thrives despite barren soil. This is because of the tropical climate, which allows for an abundance of heat and moisture. The rainforest effectively creates 75% of its own water, as the sunlight keeps the air above the forest warm and wet, in turn producing a lot of rainfall.
The world beneath the jungle canopy
As with most rainforests, the upper layers of the Amazon Jungle form a thick canopy that prevents sunlight from reaching the ground. So while the upper layers of the rainforest are a world of sunlight and flourishing vegetation, the lower parts form a dark underworld.
The majority of life lives in the canopy, feeding on an abundance of fruit and nuts growing in trees that can reach 50–60 meters high. Birds and gliding animals soar above the treeline, while monkeys and sloths live among the branches, as do a variety of insects. The trees have plants growing out of them that can survive without roots in the ground, because they feed off nutrients in the air and water from rain.
Meanwhile on the forest floor, worms, slugs and termites thrive in the darkness. Armadillos and anteaters in turn feed on these creatures. Even larger mammals such as leopards can be found slinking through the shadows.
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As for the the river itself, it offers a whole other world of lifeforms, including alligators, dolphins, manatees, otters and anacondas, in addition to thousands of fish species.
Tribes of the Amazon
The livelihoods of over a hundred indigenous tribes—many of which have had no contact whatsoever with the outside world—are dependent on the Amazon. They include the Waodani tribe (also known as the Huaorani or Waorani) who speak a language that has no linguistic links to any other known dialect; and the Tagaeri tribe, who are so determined to preserve their isolation that they attacked and killed two missionaries who attempted to make contact with them in 1987.
Other groups have been more open to outside influence. The ribereños are descended from a mix of European colonists and indigenous tribespeople, and though they still rely on the river for sustenance and transport, they have incorporated some aspects of modern technology into their lifestyles.
There are no roads in the jungle, so the ribereños use the rivers as roads and highways, as our ancient hunter-gatherer ancestors once did. The people live in villages along the river, and even the children know how to use canoes, so they can attend schools on the riverside.
The ribereños aren't the only ones who rely on waterways for transport. The city of Iquitos in the Peruvian Amazon is so deep in the jungle that it can only be accessed by river or air, making it the largest inland city in the world that is still inaccessible by road.
More Facts About the Amazon River
- Often referred to as the “lungs of the earth," the Amazon rainforest produces 40 per cent of the world's oxygen.
- Whether or not the Amazon River is longer than the Nile may be a point of contention, but there's no debate about which has the greater volume of water. 20 per cent of all freshwater that is discharged into the ocean comes from the Amazon River.
- The river is too wide for any bridge to cross, and occasionally it will flood due to melting snows at its source in the Andes, making it even wider. When this happens, there can be as much as 40 kilometres between each river bank.
- The Amazon River, when its various tributaries are taken into account, flows through nine South American countries.
- There is a massive coral reef system in the Amazon River delta (the point where river meets ocean). It was only discovered in 2016, being completely concealed by the river's sediment until then.
- Demonstrating how ecosystems across the world can be interlinked, the Amazon rainforest receives vital nutrients from . . . the Sahara Desert. That's right, dust from the desert is blown across the Atlantic Ocean to the Amazon, delivering thousands of tons of phosphorous. If a barren desert in North Africa and a thriving jungle in South America can be so inextricably linked, it only emphasizes how much of a domino effect our actions toward the environment can have.
Protecting the Lungs of the Earth
The Amazon rainforest is currently facing a significant threat to its existence. Far-right president of Brazil, Jair Bolsonaro, has pledged to strip away many of the laws protecting the forest, and open it up for commercialization. Mass deforestation has been sanctioned by the president, with little regard for the ramifications or the livelihoods of indigenous tribes.
Like many politicians of his breed, Bolsonaro has no idea of what he'll unleash if he continues on such a path, but when he does finally realize his mistake, it will be too late. That's why activist groups and policy makers who recognize the true importance of the Amazon need to be supported in their quest to halt the mad destruction.
The Nile River gave rise to a mighty man-made civilization in Ancient Egypt, while the Amazon River instead formed the heart of a thriving natural world. But while the Amazon rainforest may not be made by man, It can certainly be destroyed by man, if adequate measures are not taken to protect it.
- 10 Amazing Amazon Facts (National Geographic). Retrieved from https://www.natgeokids.com/za/discover/geography/physical-geography/amazon-facts/
- The Amazon and the River People. Retrieved from https://world.expeditions.com/destinations/south-america/amazon/the-experience/read-up-gear-up/staff-article9/
- Ellen Gray. (2015, 22 February). NASA Satellite Reveals How Much Saharan Dust Feeds Amazon’s Plants (NASA.gov). Retrieved from https://www.nasa.gov/content/goddard/nasa-satellite-reveals-how-much-saharan-dust-feeds-amazon-s-plants
- Ernesto Londoño and Letícia Casado. (2020, 19 April). As Bolsonaro Keeps Amazon Vows, Brazil’s Indigenous Fear ‘Ethnocide’ (New York Times). Retrieved from https://www.nytimes.com/2020/04/19/world/americas/bolsonaro-brazil-amazon-indigenous.html
- Amazon threats (WWF). Retrieved from https://wwf.panda.org/knowledge_hub/where_we_work/amazon/amazon_threats/
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
Andrew Spacey from Sheffield, UK on September 13, 2014:
Thank you for this. I enjoyed reading about the source of the Amazon - a river I've recently traveled down - and your descriptions of the flora and fauna. It's certainly an overwhelming river when you first face it and leaves a lasting impression.