Today in Astonishment: The Amazon Rainforest Gets Half Its Nutrients From a Single, Tiny Spot in the Sahara

By Alexis C. Madrigal

The Amazon basin is one of the world's wondrous ecosystems, supporting massive amounts of life, both in kind and quantity. You might have thought about poison frogs or monkeys, but you've probably never stopped to wonder, "Where are all the nutrients that power this biotic explosion coming from?"

The answer is actually astonishing and delightful in that one-planet-one-love kind of way. As laid out in a 2006 paper that science writer Colin Schultz dug up, nearly half of the nutrients that power the Amazon come from a valley in the Sahara called the Bodélé depression. At 17,100 square miles, the area is about a third of the size of Florida or 0.5 percent the size of the Amazon basin it supplies.

"This depression is a unique dust source due to its location at a bottle neck of two large magmatic formations that serves as a `wind lens', guiding and focusing the surface winds to the Bodélé," the authors, an international team of geologists, wrote.

This is what that looks like.

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But now let's zoom out. The dust storms that come swirling out of the Sahara can cover an area larger than the United States. That's the only scale that could deliver 40 million tons of dust from Africa to the Amazonian basin each year.

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This article available online at:

http://www.theatlantic.com/technology/archive/2012/08/today-in-astonishment-the-amazon-rainforest-gets-half-its-nutrients-from-a-single-tiny-spot-in-the-sahara/260655/