Cloud Life
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Clouds are as common as grass. But unlike grass, no one ever thought to check the clouds for living organism. That is, no one until Austrian scientist Birgitt Sattler. Hi I'm Dave Thurlow for the Weather Notebook.

Sattler analyzed cloud samples and made the incredible discovery that clouds harbor thriving communities of millions of microorganisms.

Microorganisms have been detected before in the atmosphere, but were believed to be inert. Researchers thought the freezing cold temperatures, high ultraviolet radiation, and lack of food in clouds prevented life from existing inside of them. This is the first real evidence that clouds support bacterial growth.

Sattler took samples from a cloud that went over a meteorological station on top of Mount Sonnblick, near the city of Salzburg. She gathered water droplets from an alpine cloud and froze them onto Teflon plates so that the cloud water could be studied.

Sattler discovered that each drop contained about 1,500 bacteria of different shapes and sizes. She subjected the microorganisms to radioactive versions of thymidine, a component of DNA, and leucine, an amino acid. This helped her determine that the bacteria were alive, thriving, and most likely reproducing. Her work has opened a meteorological and environmental can of worms. The bacterial activity in clouds may be influencing the climate by controlling the production and loss of alcohol, organic acids, and other substances. It could also be contributing to acid rain.

In the future, Sattler hopes to find out where the bacteria originate from, what they eat in the clouds, and what specific compounds they produce. She certainly has her work cut out for her.

Today's show was written by Diane Bowden. The Weather Notebook is a production of the Mount Washington Observatory and is funded by Subaru: The beauty of allwheel drive.