Reminds me of the Gamma Forest at Brookhaven National Labs. From 1961 thru 1978 they irradiated a section of the pine barrens forest with a cesium-137 source just to see what would happen. It sterilized the soil and hardly anything grows there, almost 50 years later.

https://maps.app.goo.gl/pJYr6qiZnMdVwLJS6

https://www.atlasobscura.com/places/brookhaven-gamma-forest

https://www.youtube.com/watch?v=GsuiLxcDuHY&t=925s

This is huge news if true for evaluating soil experiments on Mars. They could give false positives for life if they only look for metabolic products.

Obligatory Asimov: 'The most exciting phrase to hear in science, the one that heralds the most discoveries, is not "Eureka!" but 'That's funny...”'

It feels next would be trying isolate the component that make CO2. Try to use smaller sample. Put them under microscope, etc.