21 March 2006
Evolution and 'space bacteria' under the microscope
Researchers at the University of Sheffield have uncovered evidence to suggest that some bacteria in the upper atmosphere may have originated from space, and not from Earth, as was previously assumed.
In a research project led by Dr Milton Wainwright, from the University of Sheffield's Department of Molecular Biology and Biotechnology, the team analysed clumps of bacteria retrieved from the Earth's stratosphere, at a height of up to 41km. Their report, to be published this month in the International Journal of Astrobiology, proposes a new view of bacterial evolution and speculates on the origin of some bacteria.
The study discovered a number of microbes occurring in the stratosphere, which contradicts the long-held belief that bacteria are not found beyond the tropopause (at an average height of 17km.) Instead, the team show that bacteria from Earth can be transported into the stratosphere by a number of different methods. Once at this height, bacteria are exposed to increased levels of UV, increasing the chances of mutation, before they return to earth. The team suggest that this process may have contributed to, and even speeded up, evolution on Earth.
However, the report also notes that some samples of bacteria are found in clumps that are far too large to have been transported from the Earth's surface. The team suggest that these clumps of bacteria could be coming into the Earth's atmosphere from outer-space rather than originating from the Earth's surface.
Dr Milton Wainwright said: "These are extremely exciting findings from which we can learn a great deal about the behaviour of bacteria in the atmosphere, and possibly even the beginnings of evolution on Earth. This research has contributed a great deal to our understanding of exactly what is going on at great heights above the surface of the planet and I expect that it will invigorate the ongoing debate over evolution."
For further information or to arrange interviews please contact:
Matt Barker at the University of Sheffield press office on 0114 222 1046, or matt.barker@sheffield.ac.uk
« Return to news releases
|
