|At Gusev, if the craters in the area were indeed harboring conditions conducive to some special algae growth – primarily, by extending below the local water table — then one could easily speculate that as the algae mats within some craters grow in the Martian spring and summer, and ultimately reproduce, their spores are carried by the winds out of the craters … to form the long, sinuous streaks across the intercrater surfaces observed from orbit!The “streaks,” then, would simply be more colonies of algae from the craters … spread by algae spores surviving for a time between the crater floors ….
However, deprived of crucial quantities of water and essential nutrients (which, in this scenario, would be concentrated on those crater floors), the migrating algae colonies between the craters quickly die … and decompose. Through this process, they would inevitably release some of their bound organics – the hydrogen, carbon, etc. — back into the atmosphere … to be seen as significant quantities of methane gas.
During 2004 observations from the ESA Mars Express spacecraft in orbit around Mars, methane was detected in its atmosphere. And even more recently, Methane has been detected on Mars by three independent groups of scientists. And this could be a sign of life – indicating methane-producing bacteria.