The Fog Is Alive: Active Microbes Transform the Air We Breathe

The air we breathe is filled with an immense number of microorganisms, so it makes sense that a portion of them can be found within fog. New research has offered an unprecedented glimpse into this unique ecosystem.

Vibrant and Active Microbial Communities

Meteorological services typically define fog as a dense veil of water vapor that reduces visibility to less than a kilometer. In work published in the journal mBio, researchers collected a series of samples before, during, and after 32 distinct episodes, over a two-year period.

Analyses revealed that fog droplets harbored a bacterial biomass at concentrations comparable to those found in eutrophic lakes or the ocean. It turns out that representatives of the genus Methylobacterium dominate these communities, not matching any of their purely aerial counterparts.

Whereas it had been assumed up to now that these tiny life-forms were dormant and merely along for the ride, the new study paints a very different picture.

Metabolically active, these bacteria transform chemical compounds naturally present in the environment such as formaldehyde. If the latter proves toxic to us and many animal and plant species, it acts as a “food of choice” to sustain the growth of fog-dwelling life.

Further Research to Be Explored

Our understanding of the biological phenomena tied to the formation of water vapor is quite limited, so more research will be needed to explore how these microbial communities interact with their environment, though it is likely that their depolluting actions extend to other problematic compounds.

According to Ferran Garcia-Pichel of Arizona State University, with fog and mist being considered as alternative sources that could help address the global freshwater shortage, it is essential to learn more.

“By capturing them, we could get rid of these precious microscopic allies,” he concludes.

Previously, a study had explored the purifying capabilities of lightning.