Tough guys at the edge of space

According to research done by microbiologists at the American University of Maryland, among others, the stratosphere is inhabited by extremophiles that can withstand extreme cold and ultraviolet bombardment and are the furthest frontier of terrestrial life. Scientists want to develop an "Atlas of Stratospheric Microbes" that would catalog microbes that live at high altitudes.

Studies of microorganisms in the upper layers of the atmosphere have been carried out since the 30s. One of their pioneers was famous Charles Lindberghwho, along with his wife, analyzed atmospheric samples. Their team found in them, among others, spores of fungi and pollen grains.

In the 70s, pioneering biological studies of the stratosphere were carried out, especially in Europe and the Soviet Union. Atmospheric biology is currently being studied, including through a NASA project called ABOVE (). As scientists note, extreme conditions in the Earth's stratosphere are similar to those in the Martian atmosphere, so the study of stratospheric life can help identify various "aliens" outside our planet.

- - he said in an interview with "Astrobiology Magazine" Shiladitya DasSarma, a microbiologist at the University of Maryland. -.

Unfortunately, there are not many research programs devoted to living organisms in the atmosphere. There are problems with this, because the concentration of microorganisms per unit volume is very low there. In a harsh, dry, cold environment, in conditions of highly rarefied air and ultraviolet radiation, microbes must develop survival strategies characteristic of extremophiles. Bacteria and fungi usually die there, but some survive by creating spores that protect the genetic material.

— — DasSarma explains. —

Space agencies, including NASA, are currently careful not to expose other worlds to terrestrial microfauna, so precautions are taken before launching anything into orbit. In most cases, microbes are unlikely to survive the cosmic ray bombardment. But stratospheric organisms show that some can do it. Of course, it is important to remember that survival is not the same as life flourishing. The fact that an organism survives in the atmosphere and, for example, reaches Mars does not mean that it can develop and multiply there.

Is this really so - this question can be answered by more detailed studies of stratospheric organisms.