Environment

Cloudy with chance of viruses: Billions of microorganisms rain down daily

Cloudy with chance of viruses:...
A new study has quantified just how many viruses and bacteria rain down from the atmosphere every day
A new study has quantified just how many viruses and bacteria rain down from the atmosphere every day
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A new study has quantified just how many viruses and bacteria rain down from the atmosphere every day
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A new study has quantified just how many viruses and bacteria rain down from the atmosphere every day

Fresh air might not be quite as fresh as we think. Viruses and bacteria get swept up into the atmosphere in enormous amounts, and now a new study has quantified that amount, finding that untold billions of microorganisms are raining down across the Earth every day.

For decades, genetically identical viruses have been found in very distant parts of the world. Scientists determined that the bugs were hitchhiking on airborne particles that are swept up into the atmosphere and carried long distances before being deposited back to the surface.

"Roughly 20 years ago we began finding genetically similar viruses occurring in very different environments around the globe," says Curtis Suttle, senior author on the new study. "This preponderance of long-residence viruses traveling 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."

The mechanism may have been known, but it wasn't clear just how many viruses and bacteria were using this method to get around. Conducted by scientists at the University of British Columbia, University of Granada and San Diego State University, the new study set about quantifying that number.

To make any long-distance journeys, microorganisms would need to get above the whims of Earth's weather systems, which means climbing to an altitude of 2,500 to 3,000 m (8,200 to 9,800 ft). So, the researchers set up their work station high in the Sierra Nevada mountains in Spain, which can reach those elevations.

There, they found that over 800 million viruses and tens of millions of bacteria are deposited per square meter per day, from that planetary boundary layer of the atmosphere. In some cases, the rate that viruses rain down is up to 461 times higher than that of bacteria. The researchers say this is likely because viruses can cling onto smaller particles than bacteria, meaning they can stay airborne longer and travel further. Most of the viruses also showed signs of having been swept into the air via sea spray.

"Bacteria and viruses are typically deposited back to Earth via rain events and Saharan dust intrusions," says Isabel Reche, an author of the study. "However, the rain was less efficient removing viruses from the atmosphere."

The research was published in the International Society for Microbial Ecology Journal.

Source: University of British Columbia

7 comments
Sisko
Then why didn't the American Indians have any immunity to illnesses brought to them by the Europeans? They should have been raining down from Europe all through history, allowing the Indians to get used to them and developunitukk
Daishi
This is going to make it a lot harder to fight the zombie apocalypse.
Douglas Bennett Rogers
I have noticed allergens lifting off of the top of forest fires on the West Coast and travelling across the US on Pacific storms.
Skyler Thomas
Sisko, just because there are microbes adapted to move around through the atmosphere does not mean that all microbes have this adaptation.
ljaques
Luckily, the 1917 Influenza and Ebola weren't two of those virii. I'd like to know if the flu and colds go around like that, how much sarin and other bio weapons drift around, etc. How much of Hussein's (not ours, Iraq's) chemical weapons used on the Kurds made it into the atmo? What are the side effects? How many of our cancers are from weapons testing? Does this mean that a single genocidal maniac can kill the world with one bomb? Not good. The good news is that the dispersion is extreme, diluting whatever it is and rendering it less harmful in any given area.
Nik
It's not a stretch of the imagination to consider that some of these airborne bugs, might well get carried into space. From there they could eventually end up anywhere, picked up by passing comets, or similar, and eventually be drawn down into an environment that is favourable, and where they can multiply, and mutate, eventually becoming new life forms.
MBednar
We are full of microbes in our gut. My point is that all microbes aren't bad and a healthy gut relies on having these microbes. I wouldn't be alarmed, I would embrace.