Manganese oxide was found by NASA's Curiosity on Martian rocks back in 2016. Since scientists believed that oxygen was needed to produce the compound, they thought that there was oxygen in Mars' ancient atmosphere. However, new studies have disproved this.
How Initial Assumptions Were Disproved
Recent studies based on laboratory experiments show that oxygen was not necessary to form the minerals. On the contrary, oxygen would've prevented the oxygen-reliant reactions that were needed to form the minerals.
Kaushik Mitra, a planetary geochemist from Stony Brook University, said that oxidation does not necessitate the involvement of oxygen by definition. He also led the study as part of his graduate research work for Washington University.
He also expressed that the planet was red due to viable oxidants other than oxygen and UV photo-oxidation. It was only now that an alternative to oxygen was discovered to explain the formation of manganese oxide on Mars.
Disregarding the need for oxygen, scientists claimed that manganese oxide was formed due to the number of halogen elements on the Red Planet. These include chlorine and bromine, which are abundant on Mars.
Kaushik, along with other researchers, conducted experiments to prove the statements, which were derived from the idea of chlorinating drinking water. Chlorination means adding molecules with chlorine to kill microorganisms through oxidation, as mentioned in Space.
In the experiment, they created water samples that mimic the composition that could've been found on Mars. As they put manganese mineral fragments into the water, the minerals dissolved, which formed manganese oxide exponentially faster without oxygen.
They determined that the reaction was due to the water sample having chlorate and bromate, which are forms of the two halogens that are plenty on Mars. Although, it was bromate that was proven to be efficient in transforming manganese to manganese oxide.
Other than disproving the presence of oxygen in Mars' ancient atmosphere, scientists also believe that the Red Planet was rich in carbon dioxide. Even if the initial belief wasn't contradicted by the new study, carbon dioxide blocking oxygen reactions will.
Read Also: NASA's InSight Lander Transmits Potential Final Image from Mars
Did Mars Have Living Organisms Before?
There's no definite answer for that yet, but it is possible. Mitra did say that there are life forms that aren't oxygen-based. This means that previous life or habitability should not be so easily dismissed.
There are organisms on Earth that can survive without oxygen. Anaerobic organisms use fermentation or anaerobic cellular respiration to produce energy molecules (adenosine triphosphate or ATP), as mentioned in Biology Dictionary.
While most oxygen-based organisms use oxygen as a final electron acceptor, some of the anaerobic ones use sulfate ions, which explains the smell of sulfur in some areas like swamps or mudflats.
There's even a different discovery where researchers found a parasite that lives in salmon tissue. It evolved to a point where it doesn't need oxygen to produce energy, according to CNN. This can be seen as proof that life might've existed on the Red Planet even without oxygen.
Related: NASA Rover's Search for Life on Mars Allegedly Lead to Discovery of Frog-Like Rocks on Red Planet?
