The 13C isotope

Giant plumes of methane on Mars may be the belches of buried microbes

NASA is keeping an open mind, but says there is an urgent need to analyse the methane clouds for other chemicals that would either confirm or rule out life as the cause.
This was the headline for an article published in the Guardian on Thursday 15th of January 2009.

 

The picture on the right is from www.guardian.co.uk

Nili Fossae, one of the regions on Mars emitting methane. The area was already a proposed landing site for the Mars Science Laboratory because of the presence of mineral-rich clays (red). Photograph: AP/Nasa

 

 

 

In 2011 NASA launched the Mars Science Laboratory(MSL), pictured on the right.

But how to deduce whether the methane present is from an organic rather than an inorganic source?

Carbon has two stable isotopes namely 13C and 12C. The carbon incorporated in most organisms includes between 1 and 3.5 percent less 13C than the carbon in the carbon dioxide dissolved in sea water. Methane produced by organisms shows a carbon 13 depletion as compared to the methane produced from geological reactions. The MSL will look at the methane for a telltale depletion of carbon 13. This will give us a good indication as to the origin of this methane.