Bacteria Living in 'Cloud Cities' May Control Rain and Snow Patterns

Some bacteria can influence the weather. Up high in the sky where clouds form, water droplets condense and ice crystal grow around tiny particles. Typically these particles are dust, pollen, or even soot from a wildfire.


But recently scientists have begun to realize that some of these little particles are alive -- they are bacteria evolved to create ice or water droplets around themselves. Some of them live in clouds , and here and there they may be numerous enough to change rain and snowfall patterns.

Might make you think twice about trying to catch snow flakes or raindrops with your tongue.


One of these weather gifted bacteria is called Pseudomonas syringae. Known to live on agricultural crops, this bacteria does more than provide any old surface for the ice crystal to grow.

Thanks to a special protein, the bugs promote freezing at higher temperatures than usual, an attack mechanism that damages plants so the microbes can feed.

But David Sands, a scientist from Montana State University, and other researchers believe the bacteria are part of a little known weather system.

The magical ability of this protein is well known. Ski resorts use cannons to shoot this protein into the air to promote snow formation.

The fact that these bacteria employ the protein is the intriguing part (and, oh yeah, they can LIVE IN CLOUDS!) and could open up doors for more than the snow-building industry.

The most nagging question for scientists, however, is determining just how widespread this and other species of bacteria are, and how much they influence precipitation patterns. From Tuesday's New York Times article about the discovery, cloud physicist Roy Rasmussen of the National Center for Atmospheric Research said:

“The question is, do these guys get into the atmosphere in large enough concentrations to have an effect? My gut feeling is this may be important for specific places and specific times, but it’s not global.”

If bacteria really do play an important role in modifying weather patterns, it could help explain how poor land use practices like overgrazing and logging contribute to droughts. Rid an environment of plants and the microbes have nothing to eat. Strip away enough vegetation and there aren't enough bugs around to seed clouds -- and the rains disappear.

The flip side of the coin is that certain crops could be planted to encourage bacteria growth, and thus bring rain to a dry region.

"Wheat or barley might differ a thousandfold” in terms of bacteria amount, Sands said, “depending on the variety.”

But before scientists attempt to engineer weather patterns -- which could open up its own can of worms -- they must understand the full extent of these bugs' miraculous ability to work as natural rainmakers.

(Submitted by Chad Arment)