Well, in light of what the article said, (I know, I know, nobody acutally reads the articles anymore) ...
The tentative detection of ammonia comes just a few months after methane was found in the Martian atmosphere. Methane is another gas with a possible biological origin....what are some of those other possible "ten thousand things other than the existence" of life there that would be constantly giving off ammonia?Ammonia is not a stable molecule in the Martian atmosphere. If it was not replenished in some way, it would only last a few hours before it vanished.
One possibility the scientists have had to rule out is that the ammonia comes from the air bags of the failed Beagle 2 mission. Analysis has revealed that the suspected ammonia's distribution is not consistent with this explanation.
Life on Mars?
The importance of ammonia is that it is a compound of nitrogen and hydrogen.
Nitrogen is rare in the Martian environment but because no form of terrestrial life can exist without it, the presence of ammonia may indicate that Martian microbial life is hoarding it.
"There are no known ways for ammonia to be present in the Martian atmosphere that do not involve life," the Nasa scientist said.
... Lava deposited on to the surface, or released underground, could produce the gas.
But, so far, no active volcanic hotspots have been detected on the planet by the many spacecraft currently in orbit.