re: Impossible to know if the conditons found at Meridiani were uniform to Mars.
Undoubtedly in the article itself they will make comparisons to hypersaline lakes on Earth such as the Dead Sea. Can't tell from the news release how saline they are suggesting the Mars water was.
But in the Dead Sea some hardy microbes can survive:
Secrets of a Salty Survivor.
A microbe that grows in the Dead Sea is teaching scientists about the art of DNA repair.
http://science.nasa.gov/headlines/y2004/10sep_radmicrobe.htm
Bob Clark