Amazon River

As I cruised down the river, the two waterways blended into a café-au-lait mix of whitewater. While my journey covers a distance of 1000mi (1600km), it accounts for only a quarter of the river's total length. To find where the Amazon starts, I would have to travel high into the Andes Mountains of Peru. From there, it gets a little tricky because scholars and explorers have debated the source of the Amazon for centuries. Most agree that it comes from three rivers in Peru: the Marañón, the Apurímac, and the Mantaro, instead of one source.

The Amazon stretches for about 4000mi (6400km), flowing north through Peru before turning east and emptying into the Atlantic Ocean. The river is connected to a vast network of waterways that include more than 1100 tributaries, eleven of which are major rivers in their own right, each exceeding 1000mi (1600km) in length.

As a whole, the Amazon drains nearly 40% of the South American continent. Up to 20% of this freshwater is discharged into the ocean, amounting to 209,000 cubic metres per second, equivalent to 84 olympic swimming pools. In fact, the Amazon could fill 7.2 million olympic swimming pools in a single day. This huge discharge of freshwater dilutes the salinity of the Atlantic Ocean for more than 100mi (160km) offshore. This process is very important for stabilising the Earth's climate and ocean currents. Any changes in ocean currents can lead to extreme weather events, such as droughts or floods, impacting the livelihoods of communities and indigenous people that rely on a balanced ecosystem.

Interestingly, geological studies suggest that the river flowed westward, emptying into the Pacific Ocean millions of years before the Andes Mountains formed. When the South American and Nazca tectonic plates collided, it gave rise to the Andes, blocking the river's flow. Over time it changed course due east.

To Brazilians, the river section between the border of Peru and its confluence with Rio Negro in Manaus is known as the Solimões River. The name is derived from an indigenous nation called Soriman. To the rest of the world, the river's upper and lower portions are known as the Amazon.

Every year, from December to May, the Amazon River experiences a "flood pulse", where heavy rainfall and snowmelt cause the water level to rise by 30-40ft (9-12m). This flooding creates a seasonal floodplain forest inundated by whitewater rivers, called várzea in Portuguese. It's a big deal for aquatic plants, like water lilies and grasses, as the whitewater deposits nutrient-rich sediments, which help them to thrive. Várzea is also an important food source for fish, turtles, birds, and land animals. The Amazon River dolphins are in their element, swimming through the flooded trees to hunt for fish. From June to November, the water levels recede, and the river returns to its normal course.

There is much to learn about this magnificent river, but I must push on to my next destination. See you in Itacoatiara.