From desert to jungle: understand how the Sahara benefits the Amazon

This desert SaharaIt is in Africa, thousands of kilometers from South America, and yet the two continents are completely connected. In reality, Amazon rainforest it survives only thanks to the desert, and a few years ago scientists managed to understand the significance of this union.

Scientists knew that winds carried dust from the Sahara to different parts of the world, but a study published in 2015 made it possible to understand the significance of this transatlantic journey. PThe researchers discovered that the powder contains significant amounts of phosphorus.a highly relevant nutrient for survival Amazon.

The dust that feeds the Amazon

In a study published in the scientific journal Geophysical Research Letters, scientists used the CALIPSO satellite (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) to measure the amount of dust traveling intercontinentally in three dimensions. The data were obtained between 2007-2013.

The satellite uses LIDAR technology to find the amount of material and distinguish dust from other particles. So they found that phosphorus also travels intercontinental with the dust, thus helping to feed the Amazon.

Some of the dust was collected in the African depression of Bodelé, Chad, a place filled with rocky minerals composed of dead microorganisms loaded with phosphorus, according to Hongbin Yu, the study’s lead scientist, University of Maryland professor, and NASA collaborator. Miami and Barbados. So they were able to figure out an estimate of the amount of phosphorus found in the powder.

Yu said, “We must first try to answer two basic questions. How much dust is being transported? What is the relationship between the amount of dust transported and climate indicators?” said.

It is estimated that the Amazon basin receives 27,700 tons of dust annually from the Sahara, and about 22,000 tons of phosphorus falls on Amazonian soils. The data also shows that annually, winds and weather conditions transport an average of 182 million tons of dust to different regions – the equivalent of about 689,000 full trucks.

food for the planet

CALIPSO project scientist Chip Trepte said it’s important to observe windblown dust to see if there are patterns in this movement. Thus, researchers can try to understand whether these models can be used in future climate scenarios.

In the study, the scientists were able to detect dust transported from the Sahara across the Atlantic Ocean to South America. Another amount of dust was also washed into the Caribbean Sea.

“Wind currents are different at different altitudes. This is a step forward in understanding what Saharan dust transport is like in three dimensions and then comparing it to models used for climate studies,” Trepte said.

Amazonian soils are nutrient-poor, and most are found in the decomposition processes of organic matter in the forest itself. However, it is very common for rains to “wash” the soil and take up nutrients such as phosphorus.

In other words, 22 thousand tons of phosphorus that reaches the Amazon every year is very important to feed the forest. In fact, this amount is roughly the same as the amount of phosphorus lost in rainfall and floods in the region.

“We know that dust is very important in many ways. It’s a fundamental component of the Earth system. Dust will affect the climate and also climate change will affect dust. If you don’t have this African dust transport.” For the Amazon, in 10 years or 100 years, the Amazon will have lost a lot of phosphorus,” says Yu.