It is literally an ill wind that blows westward across the Sahara Desert.
Scientists have known for a century about the remarkable power of upper-level winds to carry particles great distances. But now they've found that hazardous bacteria and fungi hitchhike across the Atlantic on North African dust plumes.
"It shows we're all connected in one way or the other, much more than I would ever have dreamed before," says Eugene Shinn, one of the researchers of dust plumes at the U.S. Geological Survey.
Shinn has wondered for years about the power of upper-level winds to carry dust around the world. He and his colleague, Dale Griffin, a microbiologist at the USGS, says it could be a billion tons of dust a year.
"If you put that in other terms, there's approximately a billion Volkswagens at some point traversing some space in the atmosphere each year," Griffin says.
Red Sunsets and Lung Distress
Today the researchers say they've found something remarkable.
Tiny microbes — bacteria, viruses, fungi — are hitching a ride on those specks of dust, spreading for thousands of miles — with potentially worldwide implications for human health and the environment as well.
It typically takes five to seven days for the dust clouds to reach North America and Caribbean. Most of the dust ends up in south Florida, where it has spawned red-tinged sunsets for years.
Researchers say it's also likely that the dust causes people in Florida to have higher rates of asthma, allergies and other lung ailments. And there's evidence that dust is contributing to the deaths of coral reefs in the Caribbean.
Shinn, Griffin and their colleagues continue to conduct research they hope will shed more light on the importance of these far-reaching dust clouds.
Shinn says other scientists scoffed at him, but now they're reading his studies much more carefully.
"I was thinking about retirement a couple of years ago," says Shinn. "But I can't retire now, I've got to see this through."