Using satellite data, NASA scientists have created the first-ever 3D model showing just how much dust makes its way from the Saharan Desert to the Amazon forest. Incredibly, this dust is seeding the rain forest with an essential nutrient, an indication of just how interconnected these disparate regions really are.
Each year, wind kicks up an average of 182 million tons of dust. This amount is equivalent to 689,290 semi trucks filled with dust. One airborne, this fine particulate matter travels 1,600 miles (2,575 km) across the Atlantic Ocean. Some of it returns to the surface, but as these plumes approach the eastern coast of South America, 132 million tons of it stays in the air. Of that, 27.7 million tons, or 104,908 semi trucks worth, trickle down to the surface of the Amazon Basin. Another 43 million tons venture further north to the Caribbean Sea.
Curtains of dust: A cross section showing the configuration of the dust. The lidar instrument aboard the CALIPSO satellite sends out pulses of light that bounce off particles in the atmosphere and back to the satellite. It distinguishes dust from other particles based on optical properties. Image Credit:NASA Goddard's Scientific Visualization Studio; caption credit: NASA.
The work of University of Maryland atmospheric scientist Hongbin Yu has shown that the Saharan Desert is feeding the Amazon with upwards of 22,000 tons of phosphorus each year. That's about the same amount lost to rains and flooding. Phosphorus, which is embedded within the fine Saharan dust, is an essential nutrient that acts like a fertilizer. This dry, desert dust is literally fueling the rain forest.
It's important to note that these figures are averages. Each year experiences a huge variation in dust quantities. For example, there was an 86% difference between the highest amount of dust transported in 2007 and the lowest in 2011.
Much more in the video (above) and at NASA.