One might rethink playing with snow or walking in the rain as a new study by scientists from the Louisiana State University revealed that snow and rain might form mostly on bacteria in the clouds.

Scientists have long known that the ice crystals in clouds, which become rain or snow, need to cling to some kind of particle, called ice nucleators, in order to form in temperatures above minus 40 degrees Celsius.

Microbiologist Brent Christner at Louisiana State University sampled snow from Antarctica, France, and the Yukon and found that as much as 85 percent of the nuclei were bacteria, he said in a telephone interview with the Associated Press.

“Every snow and ice sample we’ve looked at, we found biological ice nucleators. Here’s a component that has been completely ignored to date,” Christner said.

The most common bacteria found was Psedomonas syringae, which can cause disease in several types of plants (tomatoes, green beams and other similar plants). The bacterium was found in 20 samples of snow from around the world and subsequent research has also found it in summer rainfall in Louisiana.

Scientists have sought ways to eliminate this bacterium in time. Now they wonder whether this elimination would result in less rain or snow, or would soot and dust be the major generators of precipitation.

“The question is, are they a good guy or a bad guy. And I don’t have the answer to that,” Christner said, quoted by the same source.

One thing is for sure. Bacteria that infect plants may multiply on the plants’ leaves and drift into the atmosphere. These bacteria could then cause precipitation and land on another plant, where the life cycle could continue, Christner said.

Virginia K.Walker, a biologist at Queen’s University in Kingston, Ontario, Canada said other studies have found bacteria serving as snow nuclei, but this is the first to identify it as Pseudomonas.

“It’s one of those great bacteria…you can find them anywhere. They are really interesting,” Walker said.

The study, supported by a Louisiana State University research grant and by the National Science Foundation and the Earth Institute at Columbia University, was published in today’s edition of the journal Science