If there are viruses in the soil and in the water, there are also viruses in the sky. You can’t see or feel them, but there they are. What we could not imagine is the figure. Scientists have just discovered that hundreds of millions of viruses are deposited each day in the lower layer of the atmosphere. The study has been published in the International Society for Microbial Ecology Journal.
For the first time, scientists have analyzed the large number of viruses that flit through the atmosphere, sometimes traveling even thousands of kilometers from their point of origin before seeing the planet’s surface again. To do this, the researchers looked at a boundary layer in the atmosphere, the free troposphere, which lies below the stratosphere but is still high enough to be out of reach of weather systems.
At this elevation, approximately 2,500-3,000 meters above sea level, the viruses latch onto air currents and soil particles or sea vapor and travel much farther than would be possible at lower elevations.
Experts discovered a deluge of airborne microbes: one square meter of the planet’s surface could be flooded with hundreds of millions of viruses, and tens of millions of bacteria, in a single day.
It rains more than a trillion viruses per square meter each year
“Every day more than 800 million viruses per square meter are deposited on the planetary boundary layer, that is, 25 viruses for every person in Canada, for example,” said Curtis Suttle, a co-author of the study.
However, this ‘virus shower’ has nothing to do with flu season. Viruses have existed for at least 300 million years and are abundant both on Earth and in our bodies. In fact , viruses are the most abundant microbes on the planet . The estimated total number of viruses is so staggeringly large that if all of Earth’s viruses were put together, they would cover an area of 100 million light years, according to a previous study published in the journal Nature Reviews Microbiology.
Some viruses, like the flu and Ebola, make people sick, but most only affect bacteria. Although exactly how many types of viruses there are is unknown, roughly 320,000 types of viruses infect only mammals , according to other research published in the journal American Society for Microbiology.
Viruses running through the sky
To track the invisible microbial ‘highways’ in the sky and find out how many viral passengers they were carrying, the authors of the new study placed collectors in the Sierra Nevada mountains in Spain, and collected samples of the atmosphere at altitudes of about 3,000 meters above sea level. sea , collecting floating microbes and those attached to dust and water vapor in the air.
When scientists separated and analyzed the microbial hitchhikers, they discovered that not only were there hundreds of millions of microbes covering the Earth’s surface on a daily basis, but viruses could be up to 461 times more abundant than bacteria. In the samples, the viruses attached to more organic particles, lighter than bacteria, suggesting that the viruses could stay in the air longer and therefore travel greater distances, according to experts.
Their findings also answer an age-old question about why genetically similar virus populations could be found in areas separated by great distances.
“It is quite conceivable to have a virus drawn into the atmosphere on one continent and deposited on another,” the authors clarify.
Reference: Deposition rates of viruses and bacteria above the atmospheric boundary layer. The ISME Journal – International Society for Microbial Ecology Journal. (2018) doi: 10.1038 / s41396-017-0042-4
