re: Is Mars too salty for life?
To be fair there are life forms which are happy in unbelievably salty water, but they are few and far between. New scientists take on the story gives the record as an algae which can grow in a water activation of 0.61, but also mentions that its doubtful if life could originate in such an environment. That said I've got great faith in lifes tenacity and adaptability, if there was ever a borderline habitable niche on mars I bet something will have taken advantage of it.