Gobi Desert Falls on America and Other Such Stories

Back in April of 2001, researchers watched with surprise as a dust cloud swept off the Gobi Desert in Mongolia, across the Pacific Ocean, and onto North America. This cloud of dust hampered visibility in such far-away places as Arizona.

The fact is, dust blows across the oceans to the Americas in astounding quantities every year. In one year alone more than a hundred million tons of dust from the Sahara Desert and semi-arid Sahel of Africa may settle on the Amazon River Basin, the Caribbean, and Florida.

Photo on the Left. Saharan dust blows from Africa (bottom of picture) across the Atlantic toward the Amazon forests of South America (top of picture. Image Credit NASA.

Incoming dust from the Sahara and Gobi Deserts appears to have positive effects on some ecosystems. Depleted rain-forest soils benefit from minerals in the dust that replenish nutrients washed away by heavy tropical storms. Research into peat soils in the Everglades suggests that, for thousands of years, African dust has regularly settled on South Florida. This dust not only provides needed nutrients, but it may also have affected vegetation patterns in the Everglades. The Yosemite Connection Having been a Ranger in Yosemite National Park for most of my adult life, there has to be a Yosemite connection. My friend and former colleague in Yosemite, Tom Medema, became involved with a group called Rally for Rangers. This organization provides motorcycles for rangers in wild Mongolian parks. Volunteers ride the cycles across the rugged terrain of Mongolia and deliver them to the rangers. Last year, they rode through the Gobi desert. Tom carried a prayer flag on his motorcycle and gave it to me. When I got it, it was still dusty.

That sample from the Gobi Desert came to me in a mail pouch, but dust from the same place has been blowing from Asia across the Pacific to western North America through the ages.

And now it appears to play a significant role in nourishing the forests (including Giant Sequoias) of Yosemite and the rest of the Sierra Nevada. Survival of Yosemite's trees may very well depend on the Gobi Desert.

When the granite of the Sierra breaks down to form soils, those soils are deficient in some minerals required for tree growth, particularly phosphorus. When scientists tested dust in high Sierra soils, they discovered that nearly half (45%) came from Asia (primarily the Gobi Desert). And that dust is high in phosphorous. I often muse on the thought that it takes more than the land within Yosemite to support the life that lives there. It requires the lands where park species migrate annually - deer move to the foothills of the Sierra, butterflies migrate to the Coast of California and Mexico. Songbirds migrate to Central and South America. And now we find that a substantial component of Yosemite soils come from Asia. The great naturalist, John Muir, wrote, When we try to pick out anything by itself, we find it hitched to everything else in the Universe.

The more we study, the more we learn just how complicated our environment is - that the whole world is interconnected and interdependent. Our own survival may depend on understanding this.

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Above Photo. Scientists who study dust storms have long known that Saharan dust can travel across the Atlantic to the Americas. Asian dust, however, must travel much farther to reach the same destination. In April 2001, researchers watched with surprise as dust from an Asian storm crossed the Pacific reaching as far east as the Great Lakes and even Maryland. Image Credit: NASA