There is no exception. In the mid-1970s, the Viking Lander mission's Gas Exchange Experiment detected strong chemical activity in the martian soil.
Liquid water seems to be the one element needed for the equation of life on Mars.
The presence of water there, however, is still hotly contested. Many scientists believe that liquid water does not and cannot exist on the surface of Mars today. Although surface water may have been plentiful in Mars' past, they say, the current conditions of freezing temperatures and a thin atmosphere mean that any water on Mars would have to be deep underground. Moreover, if any water ice existing on Mars were somehow warmed, it still wouldn't melt into water. The thin martian atmosphere instead would cause the ice to sublime directly into water vapor.