How Stratospheric Life Is Teaching Us About the Possibility of Extreme Life on Other Worlds


The space shuttle Endeavour hangs against Earth’s atmosphere. The stratosphere is represented by the whitish layer. Credit: NASA
The presence of microbial life in Earth’s stratosphere is not only opening up a new arena in which to study extremophiles but is also increasing the range of possible environments in which we may find life on other planets. 

By Starre Vartan | SPACE.com

That’s the conclusion of a new study that summarizes what we know about stratospheric life so far.

The stratosphere is the atmospheric zone that lies directly above the dynamic troposphere where we live, but it is mostly a mystery when it comes to the life that exists there. [Extreme Live on Earth: 8 Bizarre Creatures]

You might not realize it when you’re staring out a plane window (we fly through the lowest levels of the stratosphere when we’re cruising over 35,000 feet), but there are all kinds of micro-organisms out there, according to Shiladitya DasSarma, who is a microbiologist at the University of Maryland School of Medicine and a co-author on the new study, which is published in the journal Current Opinion in Microbiology.

„Generally, people don’t think of microbes being airborne,“ he told Astrobiology Magazine. „But there’s a saying in microbiology: Everything is everywhere.“

However, there are „very few studies at the present time“ that look at the atmospheric biome. Part of the issue is that there is a low density of cells in a large volume of air. But when you look at it globally, the numbers are significant: 1021 is the current estimate for the number of cells lifted annually into the atmosphere.

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