Feeling uneasy in the mist? Does it seem as if an unseen presence lingers there? Your perception is accurate: scientists have confirmed that ordinary fog is, in fact, a living entity. However, there is nothing sinister about this substance; on the contrary, fog serves to purify the air. And you will be surprised by precisely how it achieves this. The article detailing these findings was published in the journal mBio.
WE INHALE BACTERIA
The atmosphere is teeming with bacteria. It’s not just the air we breathe; researchers have found bacteria at altitudes reaching 40, and even 80 kilometers. But what exactly are they doing up there? The silent assumption was that they were merely traveling—swept upwards by air currents. Essentially, the atmosphere could function perfectly well without bacteria. And fog, especially, had never been linked to bacteria before.
Thi Thuong Thuong Cao, while a graduate student at Arizona State University, recognized an opportunity in this unexplored territory. She collected fog samples before dawn and examined the ephemeral material that settled on the inside of her test tubes under a microscope. Now, as a postdoc at Virginia Tech, she is finally publishing her paper, the core conclusion of which is this: fog is alive.
LIFE EVERYWHERE
It turned out that only about one out of every hundred fog droplets (which are microscopic, around one-thousandth of a millimeter) contains bacteria. But there are countless droplets. When tallied, the overall concentration is no less than that found in the ocean. In a single thimbleful of water collected from the fog, the researcher elegantly phrases it, there are no fewer than 10 million bacteria.
The study was not as straightforward as one might assume. The scientist took air samples before, during, and after periods of fog, but wind frequently complicated the results. She had to focus on the type of morning fog that settles in valleys on windless days.
The most astonishing finding of the research is that bacteria are not simply adrift in the fog due to being carried there; they actively live and multiply within it. Consequently, fog has proven to be not just a meteorological event but a genuine biome.
GUARDING OUR HEALTH
So, what is their purpose there? Cao paid close attention to one group of bacteria that seemed particularly thriving in the fog—methylobacteria. Significantly, the quantity of these bacteria in the air increased following a fog event compared to before one.
Methylobacteria have long been known to scientists and are utilized, for instance, as a component in “bio-fertilizer” to promote plant growth.
They possess a truly indispensable property: they consume substances that negatively impact us. This includes methanol, methane, and even formaldehyde. What they consume is partly converted into energy for the bacteria’s survival, and partly transformed into carbon dioxide (beneficial for plants), water, phytohormones, and even vitamins (also useful for flora).
“We observed them under the microscope and confirmed that the bacteria truly increase in size and divide, meaning growth is occurring,” states Cao. “We also discovered that they utilize formaldehyde as sustenance to maintain this growth.”
PROTECT THE FOG
Cao believes her research opens up many new considerations. For example, substantial efforts are currently underway to devise methods for harvesting water from morning fog—a project relevant more to places like the Sahara than to Russia. Companies are already marketing their equipment for this purpose. However, Cao suggests now is the time to pause: the benefit derived from this collected water may be completely outweighed by the harm inflicted by equipment that deprives the local environment of these useful bacteria.
The investigations are ongoing, and much remains unclear. According to conventional understanding, nighttime causes chemistry to “pause”: without the sun, all the “actors on the chemical stage” are dormant. But this clearly does not apply to methylobacteria. Apparently, scientists have uncovered an unexpected nocturnal ecosystem that cleans the air and supports plant life when life-giving sunlight is absent.
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