Dust storms and ocean spray lift viruses into atmosphere by the millions, study says
UBC research explains how genetically identical microbes can be found around the world
How does a virus from one side of the planet end up on the other? Giant clouds of these microbes are travelling thousands of metres above us, according to new research.
The study, a collaboration among researchers at the University of British Columbia and associates in Spain and the U.S., shows that more than 800 million viruses per square metre are being deposited into the atmosphere every day.
"We're looking up at, say, 3,000 metres in the atmosphere that these viruses and bacteria are essentially getting swept off the surface of the earth," UBC virologist and co-author Curtis Suttle told CBC News.
"If there's that many circulating that high in the atmosphere, then there's a lot more of them that are circulating close to the surface."
Bacteria are carried this way too, but the research suggests that happens in much lower numbers.
The new study, published last week in the International Society for Microbial Ecology Journal, was inspired by the knowledge that genetically identical viruses can be found all around the globe.
The microbes are carried into the free troposphere — just below the flight paths of jets — on the backs of particles from ocean spray and dust storms, according to the researchers. They fall down again with dust intrusions and rain.
"It's not unusual, say, if you have a dust storm in the Sahara to actually be able to collect the dust in the U.S.," Suttle said. "The viruses and the bacteria would be able to be carried presumably even farther."
The viruses involved are largely ones that infect other microbes, not humans.
Suttle said it's possible human diseases could be carried this way as well, but in tiny numbers — and very few would be likely to survive the trip.
"If, in fact, they were being transported in large numbers, then everybody would be getting sick all the time," he said.
The research was conducted from platform sites in Spain's Sierra Nevada Mountains.