Saharawi dust in the Amazon rainforest
2007/01/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria
Mineral dust from the Sahara desert is essential for the Amazon rainforest. This powder contains minerals and nutrients that enrich the soil and without them the Amazon itself would become a humble desert. For the first time they have shown that half of the dust that reaches the Amazon comes from a specific place in the Sahara: From the depression of Bodélé, which is barely 1% of the desert.
They knew that Bodélé was the largest source of dust in the world, but so far no one knew how much dust was extracted from there or how much was coming to the Amazon. To do this, the researchers have calculated the wind speed and the amount of dust from the data of two satellites that take pictures of the same surface three hours apart. It is found that each day of dust extraction can be exceeded an average of 0.7 million tons, and that in winter and spring it leaves more than in other seasons.
The most important factor for the transport of dust is wind speed. To reach the depression of Bodélé, the winds of Harmattan that travel the valley between the Tibesti and Ennedi mountains have to pass through a narrow conical pass that, like the lens with light, strengthens and accelerates the wind towards the Bodélé.
There are still questions on this topic: how long does that depression send dust to the Amazon? And how long will it take? To answer these questions, researchers work today.
