Bacteria can produce rain

Without leaving the ground, bacteria can still produce rain if the chemicals they release into the air reach the locations of the clouds.

Some previous studies have shown that bacteria can affect cloud formation. For example, Pseudomonas syringae has a protein that binds water molecules, turning them into grid-like structures. So ice can form at temperatures above 0 degrees C. When ice crystals (with bacteria inside) fall off the clouds, they create snow or rain (if the ice melts).

Barbara Nozière, an expert at Stockholm University (Sweden) and colleagues, judged that the chemicals that many types of bacteria produce on their surfaces can affect the weather. The main function of these chemicals is to transport nutrients through cell membranes, but they are also capable of breaking the surface tension of water. According to the research team, if chemicals exist in the cloud, it can be concluded that they are involved in the formation of raindrops.

To see if the chemical that bacteria secrete exists in the atmosphere, Barbara took air samples above a coastal area, an ocean, a tropical forest in Brazil. The analytical results show that samples contain a small amount of compounds with chemical structure similar to those on the surface of bacteria. They also create water drops in the same way.

The team thinks that during evolution, bacteria form the ability to take water from above so they can survive. The next step is to understand how chemicals that bacteria secrete into the clouds. The wind can lift cloud-producing molecules up, but they only account for a small percentage. So surely they have to fly to the sky by another means.