Behind the Forecast: It’s raining viruses? Well, kinda

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Science Behind the Forecast: It's raining viruses? Well, kinda
Microbes in the air can help clouds form before returning to the surface with precipitation.
Microbes in the air can help clouds form before returning to the surface with precipitation. (Source: Pexels)

LOUISVILLE, Ky. (WAVE) - Don’t freak out, but there’s an entire world of microbes flying over your head right now. Here’s a crazier thought: they can potentially influence the weather!

Scientists have known for centuries that microbes are in the air flowing through our atmosphere. However, within the past decade, studies have been able to quantify their presence.

There are thousands of species of microbes and fungi in rain and clouds. Many can survive the radiation, harsh temperatures, and low oxygen in the upper levels of our atmosphere.

A 2018 study found that more than 800 million viruses are distributed per square meter above the planetary boundary layer, which is the lowest part of our atmosphere. That’s enough for 25 viruses for each person in Canada. Keep in mind that more people live in California than in Canada. Viruses and bacteria are thrown into the atmosphere along with sea spray and dust.

These viruses are taken more than 2,500 to 3,000 meters into the air, allowing them to travel further around our planet. Another study noted that scientists found microorganisms five to 10 miles above the surface. Sixty percent of the cells found were alive, about the amount found in alpine snow.

Clouds typically begin to form at higher altitudes, where ice crystals can form. For clouds to form, they need condensation nuclei. Dust, sand, ash, or salt can serve as nuclei, but so can microbes.

Scientists have found some microbes that mimic ice crystal’s structure, allowing ice and clouds to form at warmer temperatures and lower altitudes.

Eventually, these ice crystals fall through clouds and to the ground once they are too heavy as snow, sleet, graupel, or rain. The precipitation brings the microbes back to the surface.

In 2010, scientists collected microbes during nine flights near and over the United States during Hurricanes Early and Karl. Most of the microbes found were comparable to those observed in freshwater or oceans. However, after Hurricane Karl traveled over populated Caribbean islands, a quarter of the microbes found were similar to the ones found in feces.

These viruses are not the ones that typically get us sick. Viruses are very much abundant on Earth and are vital to our ecosystem.

It is unknown why the amount of microbes relative to other particles is much higher at higher altitudes. Some researchers postulate that it may be because other particles are more likely to help with cloud formation and thus fall with precipitation.

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