Oddly enough the investigators did discount that hypothesis, or something close to it. The ammonia does not come from any of the landers. It is, in their view, either volcanic or biologic, the evidence doesn't swing either way as yet. Some questions they raised are, first, ammonia should be unstable in the Martian environment- therefore if it is really there, then something is replenishing it. It is the end point of ongoing processes, not a relic of the past. Second, what is the nitrogen source? If Mars is volcanically inert (?) the remaining source of methane and ammonia would be from some form of life. Are there volcanic gaseous emissions that do not have a biological counterpart, or conversely, biological gases that are never made geologically? I don't know, but this might help shift the balance of evidence one way or the other.

PS. Imran, I don't think I have ever seen two identical posts sent out at exactly the same time (within less than two minutes) on the exact same topic. Talk about synchronicity
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