Could the reddish hue of the Martian surface be due to biogenic oxygen?
Basically, nanophase ferric oxides are the mineralogic component of the thin layer of Martian surface dust that cause the reddishness of the surface. These oxides do not require free O2 to form, as thin films of brine (overnight H2O frost is fairly common on Mars, and can turn to a brine with melting point depression from soluble salts present in dust grains) and hydrogen peroxide (H2O2) can act as oxidizers. In addition, trace amounts of O2 can also be produced abiogenically. More details are available online.
After learning the ropes in physics at Wabash College, IN, Suniti Karunatillake enrolled in the Department of Physics as a doctoral candidate in Aug, 2001. However, the call of the planets, instilled in childhood by Carl Sagan's documentaries and Arthur C. Clarke's novels, was too strong to keep him anchored there. Suniti was apprenticed with Steve Squyres to become a planetary explorer. He mostly plays with data from the Mars Odyssey Gamma Ray Spectrometer and the Mars Exploration Rovers for his thesis project on Martian surface geochemistry, but often relies on the synergy of numerous remote sensing and surface missions to realize the story of Mars. He now works at Stonybrook.