The Amazon region provides about 30% – 40% of the world’s oxygen and one-fifth of its freshwater. Despite its crucial importance, we still know very little about it.
The largest tropical rainforest in the Amazon has been heavily devastated by human activity. The remaining area is maintained by a complex water cycle that we have only just begun to understand.
A parrot in the Amazon rainforest (Photo: Juan Carlos Vindas/Getty Images).
However, human activities are altering this natural cycle before we fully understand it.
The rivers and tributaries of the Amazon rainforest store about one-fifth of the world’s freshwater, nourishing numerous species of mammals, birds, plants, and amphibians.
47 million people living in the basin of these rivers also depend on its ecosystem, which includes mountainous forests, wetlands, and river systems spanning nine South American countries.
The complex hydrological climate system here traverses the terrain, including the Andes Mountains, the Amazon lowlands, and the Atlantic Ocean (referred to as the AAA Pathway). This system circulates water molecules from the Earth’s surface into the atmosphere and back to the surface. Researchers have compared this system to a steam pump, generating rainfall for the entire region.
1) Water vapor rises from the Atlantic Ocean and condenses in the atmosphere. This process is accelerated by warmer surface water temperatures. 2) “Rivers” of water vapor carry moisture westward and gradually turn into rain. 3) These vapor rivers are supplemented with moisture from the Amazon rainforest. 4) The vapor rivers reach the Andes Mountains and change direction southward, releasing rain in the “hot spots” along the eastern slopes. 5) The vapor rivers continue to move outside the Amazon basin to central Brazil and the La Plata basin in southern Brazil. 6) Rivers originating from the Andes have a significant flow, carrying nutrients and sediment for vegetation. 7) The river system in the Amazon transports water, sediment, and nutrients from the plains to the Atlantic Ocean.
Hydrologist Claire Beveridge from Florida International University states that until now, most research and conservation efforts have focused on terrestrial tropical forest communities, but the existence of the rainforest depends on the AAA Pathway.
This multidirectional water cycle not only provides rainfall but also facilitates soil movement, from the Andes Mountains, through rivers, into forests, and ultimately to the sea. These nutrient waves flow with the water, sustaining diverse populations of organisms both on land and underwater.
The AAA Pathway contributes about 40% of the sediment flowing into the Atlantic Ocean, significantly impacting many nutrient cycles in the ocean.
According to researchers, the Amazon river system stretches for thousands of kilometers into the Atlantic, and the elements associated with this river system play a crucial role in maintaining the ocean’s balance and its capacity to absorb carbon dioxide.
Although the Amazon region experiences cycles of flooding and drought due to El Niño and La Niña weather patterns, these natural cycles are not entirely responsible for the changes occurring in the area.
Rising temperatures, especially in the southern region, are amplifying changes in the AAA system. This leads to record flooding in the north, while extending droughts and wildfire seasons, increasing the risk of glacier melt in the Andes Mountains.
Deforestation and other changes in land cover also affect the AAA system, exacerbating climate change.
Researchers warn that changes along the AAA pathway and their cumulative impacts are occurring at a faster rate than the ecological-social systems can adapt. As a result, these systems are increasingly threatened and may struggle to recover.
Researchers call for more in-depth investigations into the AAA Pathway, an immediate halt to deforestation, and the implementation of restoration programs in vulnerable areas. The goal of maintaining moisture in the Amazon river basin is critically important in global efforts to mitigate climate change.
