Please please please fix this article -- it's embarrassingly wrong
This study was performed by the curiosity rover on Mars:
Essentially, there was some data indicating methane was present on Mars. Since methane is usually biologically produced, it was interesting to see if methane was actually present. Curiosity did not find much. Does this mean nothing is living or could live on Mars? Nope, just that there isn't methane.
Popular Science wrote up a summary:
They took that data and inferred, not incorrectly, that there will be little chance of finding methane-producing organisms on Mars. They even said "There are micro-organisms that don't produce methane, so we're not totally giving up on the possibility of Martians just yet." Unfortunately, this tone may have confused the writers at The Verge:
These guys took it even further with their inflammatory headline "Life on Mars? Curiosity's latest finding says probably not." They go on to say, "the most common form of microbe [methane producer] is nowhere to be found on the Red Planet" and "There's also the chance that Mars is hosting a form of microbe that doesn't produce methane, which are extremely rare but have been discovered on Earth before," which are flat-out wrong. Absolutely stupid. The only organisms that can produce methane to yet be discovered are methanogenic archaea, which live in the silt at the bottom of the ocean and in the rumens of cows, etc. Colloquially, one might say there is a shit-ton of life on earth that has nothing to do with methane production. Aside from the fact that life on other planets may not look like what we expect, The Verge, a publication full of decent, smart people, just completely made up facts.