VANCOUVER — This study will make you think twice about stepping outside for a breath of fresh air. A team of scientists from around the world confirmed millions of viruses rising into the atmosphere, traveling — sometimes for thousands of miles — and falling back down to the surface.
The study, carried out by researchers from the U.S., Canada, and Spain, is the first of its kind to confirm viruses are being swept up into the free troposphere — the layer of atmosphere between the area where Earth’s weather systems develop — and below the stratosphere, where airplanes fly.
The numbers are “astonishing” the researchers say, but remember, a virus is a tiny particle, little more than a strand of DNA and a mechanism for attaching to organic matter.
“Every day, more than 800 million viruses are deposited per square metre above the planetary boundary layer — that’s 25 viruses for each person in Canada,” says University of British Columbia virologist Curtis Suttle, lead author of the study, in a media release.
Scientists have been finding genetically similar viruses in disparate parts of the planet.
“Roughly 20 years ago we began finding genetically similar viruses occurring in very different environments around the globe,” says Suttle. “This preponderance of long-residence viruses travelling the atmosphere likely explains why—it’s quite conceivable to have a virus swept up into the atmosphere on one continent and deposited on another.”
Suttle and his team found that viruses and bacteria are often swept up into the atmosphere by attaching themselves to particles in soil dust and sea spray. The researchers used platforms in Spain’s Sierra Nevada Mountains to detect how many viruses and bacteria were settling there every day. They found billions of viruses and tens of millions of bacteria being deposited there per square meter every day.
“Bacteria and viruses are typically deposited back to Earth via rain events and Saharan dust intrusions. However, the rain was less efficient removing viruses from the atmosphere,” adds study author Isabel Reche, a microbial ecologist from the University of Granada.
The full study was published in International Society for Microbial Ecology Journal.