Microorganisms often commit a walk in the clouds. Some people are just waiting for the return to a more traditional solid earth, and others actively engaged with the world, for all its strangeness. This is no small feat, given the terrible cold, intense UV radiation, acid, caustic water.
Thus, perhaps, the microbes have an impact on how clouds are formed and behave.
As you know, very small particles that enter the atmosphere act as "cloud condensation nuclei» (cloud condensation nuclei), that is a kind of seeds, promotes the formation of droplets that make up clouds. In the tiny beads of water interact dissolved substances that affect the physical properties of the drop: and how it reflects the light, and its ability to rise and fall with rain. Reactions can also lead to the evaporation of the liquid, then the particle will again be ready to condense moisture on itself.
Previous studies have shown that the bacteria (which can also act as condensation nuclei), living in cloud water, able to participate in this chemistry, despite the cold and ultraviolet radiation. However, the experimenters still ignores the important ingredients of cloud cocktail: hydrogen peroxide and hydroxyl radicals generated by UV radiation. These substances are toxic to cells.
Therefore, a group of French researchers has produced samples of cloud water at the top of the Puy-de-Dome — a volcano in central France. Half of the samples were filtered so that they had no life, and that they become the basis for comparison. The latter part has been exposed to ultraviolet radiation (for the creation of free radicals), and the other part was placed in a dark place.
Within a week, 12 hours specialists conducted an analysis of the chemical composition of water. Measurements of ATP and ADP (components of the metabolic cycle of bacteria) shows that the body all the while still alive, despite the seemingly unfavorable conditions.
In all samples of hydrogen peroxide over time is reduced even in the absence of splitting its UV-radiation, since it reacts with other compounds. But it was clear that much of the peroxide is decomposed by the bacteria. This is probably a kind of defense mechanism: once in the conditions of a certain chemical stress, cells produce an enzyme that helps to neutralize the oxidants (hydrogen peroxide and hydroxyl radicals).
The presence of UV radiation (and, consequently, hydroxyl radicals) does not affect the stability of most of the organic compounds present in the droplets. The only "enemies" of the latter were the bacteria feed on them.
Thus, bacteria are likely to really active in the clouds. And they are not just there to survive, but have a significant impact on the chemical processes in the drops of water: controlling the concentration of hydroxyl radicals to form particles that may in the future become condensation nuclei (such clouds will have a highly reflective and therefore hardly become rain clouds).
The study is published in the journal PNAS.
Prepared according to Ars Technica.