Methan bacteria can survive under the environmental conditions of Mars

(New study) - A new study found that methane bacteria - one of the simplest and oldest organisms on Earth - can live on Mars.

Methanogens - Archaea's microorganisms, use hydrogen as their source of energy and carbon dioxide as a source of carbon, to metabolize and produce methane, a natural gas. Methanogens live in marshes, but they can also be found in the gut of cattle, termites and other herbivores as well as dead and rotten items.

Methanogens are anaerobic bacteria , so they do not need oxygen. They do not need organic and non-photosynthetic nutrients, suggesting they can exist on subsurface environments and are therefore ideal candidates for living on Mars.

Rebecca Mickol, a doctoral student in space science and planet at the University of Arkansas, tested two species of methane bacteria with the environmental conditions of Mars: Methanothermobacter wolfeii and Methanobacterium formicicum . Both species survived the freezing and thawing cycles of Mars that Mickol simulated in her experiment.

These bacteria were tested for tolerance to freezing-thaw cycles, below the ideal growth temperature of organisms: 37 degrees C (98.6 degrees F) for M. formicicum and 55 degree C (131 degrees F) for bacteria M. wolfeii.

'The temperature of the Martian surface varies widely, from minus 90 degrees Celsius to 27 degrees Celsius in a day,' Mickol said. 'If there has ever been life on Mars or there is life on Mars, at least that life must survive within the above-mentioned temperature range. The existence of two species of methane bacteria after undergoing a prolonged freeze-thaw simulation cycle shows that these bacteria are capable of living under the surface of Mars. "

Mickol conducted the study, working with Timothy Kral, professor of biological sciences at the Arkansas Center for Space Science, Planetary Science and the project's chief scientist. She presented her research at the Congress of Microbiology Association 2014, held from 17 to 20 May in Boston.

These two bacteria were selected because one of them is heat-resistant bacteria, thriving under extremely hot temperatures, and the other bacteria are thermophilic bacteria that grow under warm temperatures.

"Low temperatures on Mars inhibit the growth of these bacteria, but they still survive ," Mickol said. Once they return to warm temperatures, they can grow and metabolize again. I want to study whether Mars 'low temperature levels can kill these bacteria, or that they can survive and adapt.'

Since the 1990s, Kral has studied methane bacteria and tested the viability of these microorganisms on Mars. In 2004, scientists discovered that methane in Mars's atmosphere, and questioning the origin of these gases, became an important issue.

'When they found this out, we really enjoyed it because you asked the question,' Where did Martian methane come from? ' , Says Kral. 'One possibility is from methane bacteria'.

Mickol is currently working at the Kennedy Space Center in Florida. Her research is funded by NASA's Exobiology Program.