On ancient Mars, water carved channels and transported sediments to form fans and deltas within lake basins. Examination of spectral data acquired from orbit show that some of these sediments have minerals that indicate chemical alteration by water. Here in Jezero Crater delta, sediments contain clays and carbonates. The image combines information from two instruments on NASA's Mars Reconnaissance Orbiter, the Compact Reconnaissance Imaging Spectrometer for Mars and the Context Camera.NASA/JPL/JHUAPL/MSSS/Brown University
NASA-supported researchers at the University of Arizona have modeled the effects that methanogens could have had on the environment of ancient Mars if they had been present. From studying Earth, astrobiologists know that the activities of microorganisms can have wide-spread and lasting influence on a planet’s global environment.
On Earth, hydrogen-based methanogens produce methane as they consume hydrogen and carbon dioxide. This process is one of the earliest known metabolisms on our planet. The recent study looks at how similar organisms could have affected the habitability of Noachian Mars (a period from about 4.1 to 3.7 billion years ago) if they had been present on the red planet.
The team modeled this theoretical scenario and found that the subsurface of Mars would likely have been habitable and that bioproductivity could have been as high as it was in the early Earth’s oceans. However, methanogenesis would’ve affected Mars’ atmospheric composition and caused a global cooling event that ended the planet’s early warm period. This, in turn, would have forced microbial populations deep underground.
The authors also identify lowland sites at low-to-medium latitudes that could be great places to look for signatures of such early life at or near the martian surface. The study, “Early Mars habitability and global cooling by H2-based methanogens,” was published in the journal Nature Astronomy.
To read more about the findings, click here to view a post from Many Worlds.
The Many Worlds Blog chronicles the search for evidence of life beyond Earth written by author/journalist Marc Kaufman. The “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, a research coordination network supported by the NASA Astrobiology Program. Any opinions expressed are the author’s alone.