Life on Mars? We may have found it - and killed it, report says by Tom Paulson Seattle Post-Intelligencer 01/08/07:
"It's a plausible hypothesis that explains the Viking results quite well," said Dirk Schulze-Makuch, an astrobiologist at Washington State University who studies the interplay of microbes, water and geology. Schulze-Makuch spoke Sunday at the American Astronomical Society meeting, which continues through Wednesday in Seattle. ...
A previously confusing finding on Mars by the Viking Landers was evidence of chemical oxidation. ...
Schulze-Makuch and Houtkooper suggest that the hydrogen peroxide detected by Viking could have come from killing Martian microbes that, like some peculiar creatures on Earth, use hydrogen peroxide the same way humans use water.
The Mars landers did all their chemical analyses by mixing samples with water - a step that would have prompted a powerful chemical reaction in any microbe full of hydrogen peroxide, killing it and releasing the peroxide.
"Something had to oxidize for Viking to get those results," Schulze-Makuch said. Since nothing in Mars' soil or atmosphere appears capable of causing such a reaction, he said it's reasonable to suggest that it could have been a Martian microbe.