Rain and its incredible power to spread soil bacteria

At the Massachusetts Institute of Technology (MIT), a team of researchers published a study revealing the very important role played by rain in the dissemination of soil bacteria.

In Boston, United States, a team of researchers from the Massachusetts Institute of Technology (the famous MIT) offers an explanation for the problems of contamination of plants, animals and humans by pathogenic elements. One element probably plays a very important role in this dispersion of bacteria: it is rain.

In the review NatureCommunications, these researchers report their experiments in the laboratory on the effects of the impact of drops on the earth. They thus recreated different forms of rain, falling from different heights on soils of different natures (sand, clay, asphalt, etc.), all loaded with colonies of bacteria.

It is then observed that after the impact on the ground, each drop of rain rebounds like an aerosol, breaking into a multitude of droplets which disperse in the surroundings at more or less distant distances depending on the force of the wind. When the raindrop turns into this aerosol, it has already trapped several thousand bacteria which then disperse and are able to survive for more than an hour before reclaiming soil to colonize again.

According to these findings by MIT scientists, they estimate that precipitation on a global scale could be responsible for the dispersion of approximately 1 to 25% of all bacteria dispersed from the soil. Thus, this concerns between 10,000 and 800,000 billion billion bacteria per year. The difference depends essentially on the nature of the ground on which the rain fell. For example, a sandy soil is less favorable to a large dispersion of bacteria, the latter having the ability to absorb drops before they reach this “aerosol” stage.

The intensity of the shower, but above all the temperature on the ground also have a share of responsibility in the dispersion. According to their analyses, the dispersion is maximum when the temperature is 30°C in light rain.

Check out the experience in the video below:

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