One of the interesting things recently on the topic of Martian water is that perchlorates are present in enough quantities to keep water liquid at Martian temperatures and pressures. Some think that precludes life but it would depend a lot on when the compounds formed. Did they form in the early years of Mars or at a later time? If they formed late any life present would have had time to adapt to changing conditions. If they were there from the beginning then (according to current theories) life may not have been able to form in the first place.