Martian Soils Point to Ancient Acid Ocean--And a Dearth of Life.
"Despite being separated by thousands of kilometers, Martian soils from Gusev Crater and Meridiani Planum have proved broadly similar in parts--rich in chlorine and sulfur. Recent high-precision measurements have shown that phosphorus--the critical energy carrier in all known forms of Earth life--is equally abundant in such patches of Martian dirt. And the only explanation for such similar soils in disparate locations is a large, acidic ocean, according to a new paper published today in the November issue of Geology."
http://www.sciam.com/article.cfm?chanID=sa003&articleID=000A1326-800A-153E-800A83414B7F012F

Bob Clark