Bacteria bring rain

Tiny ice crystals form around the bacteria, which attract more water droplets to them and keep growing. When they become too heavy, they fall to the ground in the form of rain

For a long time we have been aware of the involvement of microorganisms, such as bacteria and fungi, in all areas of life. Yeast produces alcohol for us, fungi live in interrelationships with many trees and help them grow, bacteria exist in our gut and digest the harder to digest food for us and the plankton provides a huge amount of oxygen to the atmosphere. But in a recent study, it was discovered that some bacteria have the ability to directly affect the Earth's climate.

The study was published last week in the prestigious journal Science, and it confirms the bio-sediment theory. Simply put, the study finds a connection between bacteria and rain. According to Brent Christner, the author of the article and a professor of biological sciences at the University of Louisiana, there is a rich reservoir of bacteria in the atmosphere. Tiny ice crystals form around the bacteria, which attract more water droplets to them and keep growing. When they become too heavy, they fall to the ground as rain. The bacteria that survive the process and fall on plants form colonies, and these are carried away by the wind and returned to the atmosphere. This is how the bio-sediment cycle repeats itself.

Although the idea itself was proposed 25 years ago by David Sands, it was not taken seriously by most scientists. In the new study, Chrisner examined precipitation from different regions of the world and showed that the most effective ice nuclei for creating rain are biological in origin. The discovery is of great importance, since the formation of ice crystals in the clouds is necessary for the fall of snow and most precipitation. Dust and soot particles can also catalyze ice nucleation, but biological particles can form ice at higher temperatures.

The research may affect the way we see ecosystems, and how we can change them. Subsequent research and biotechnological developments will be able to reduce the desert areas and increase the creation of rain in the world, with the help of encouraging the bio-sediment cycle. Bacteria growth sites located in windy areas could provide catalysts for the rain to fall. The rain will contain those bacteria that will return to the original growth sites, and thus the cycle will repeat itself.

The conclusions from the research open another door to thought, among other things due to the fact that most of the bacteria that form ice crystals in the clouds also cause diseases in plants. Until now, research on plant diseases has focused on the stage when the bacteria are already in the plant, but ignored the way they reach the plant. Now it seems that the bacteria that cause diseases in plants have a phase of transmission through the entire atmosphere. In this way, the bacteria can travel a very long way - the entire length and breadth of the earth - in a very short time.

Similar models have also been proposed regarding the causes of various infectious diseases in humans, such as the influenza virus which is transmitted around the world in different ways. The possibility cannot be ruled out that among the various microorganisms involved in the biosediment cycle, bacteria and viruses that cause human diseases will also be discovered. Mathematical models that will be developed accordingly will be able to predict the migration of infectious diseases in the atmosphere, similar to the way forecasters today predict the coming of rain.

Brent Christner's research sheds new light on the relationship between living organisms and the Earth's climate and provides further evidence of the direct and continuous relationship that exists between us and our environment.

For a message from the University of Louisiana