Scientists have discovered a significant number of bugs living in the middle and upper troposphere, the airy layer eight to 15km above the Earth’s surface. The microbes could have a previously unrecognised impact on cloud formation.
Long distance travel by the airborne organisms may also help spread infections around the world, researchers believe.
The bugs were discovered in air samples scooped up by a DC-8 aircraft flying over both land and sea across the US, Caribbean and western Atlantic.
Scientists are still unsure whether the bacteria and fungi they found routinely inhabit the sky, living off carbon compounds, or are continually borne aloft by winds and air currents.
“We did not expect to find so many micro-organisms in the troposphere, which is considered a very difficult environment for life,” lead researcher Dr Kostas Konstantinidis, from the Georgia Institute of Technology in the US, said.