Image: NASA
Huge dust clouds swirling across the Atlantic from northern Africa to South America are pictured in stunning new images released by the US space agency Nasa, illustrating how Earth's largest tropical rainforest relies on its biggest, hottest desert to flourish.
Scientists have now, for the first time, calculated how much dust makes this transatlantic journey from the Sahara to the Amazon basin where it fertilises depleted soils.
Some 27.7million tons of the dust carrying about 22000 tons of phosphorus makes the journey from one of the planet's most desolate places to one of its most fertile.
The same amount is washed away in flooding each year.
"This is a small world and we are all connected," said Hongbin Yu, an atmospheric scientist at the University of Maryland who works at Nasa Goddard Space Flight Centre.