From Jill Banfield:

Re: Mars salt might have thwarted life (Feb. 15): Certain microbial communities are adapted to life in water saturated with salt and thrive in battery acid-like solutions (pH <1). For this reason, researchers working within the NASA Astrobiology Institute are investigating hypersaline lake sites, which may have some characteristics analogous to those that would have prevailed at the surface of Mars as its oceans disappeared. So while “not all water is fit to drink”, most water is inhabitable by microbes. Contrary to the opinion stated in this article, these findings do not ‘tighten the noose on the possibility of life’, rather they focus the search.