Op-Ed: Oxygen release on Mars – New options for life?

Cape Canaveral - The discovery of variable oxygen levels on Mars has created a fascinating, if frustrating, series of possibilities for science. Are the oxygen levels related to organic life, or some unknown inorganic process? 

 

The discovery by the Curiosity rover has reignited the debate about life, and there’s plenty to work with. Oxygen levels rose by 30% in the Martian spring and summer. It obviously had to come from somewhere, and that origin is the big issue on which future science may have to work. Mars doesn’t have a lot of oxygen now. It did have a lot more in the past. It has a very thin atmosphere, almost non-existent by Earth standards. It’s also not a particularly hyperactive world, in terms of variations. What usually happens are dust storms, well-studied polar ice variations, etc. The discovery of large variations in anything, let alone oxygen, is therefore a very big deal. It suggests unknown chemistry, obviously, but also on a large scale. The fact that the discovery was made in the Gale crater may also have a bearing on the issue. Is this a microclimate phenomenon, or something bigger? Organically derived oxygen? It would come as no big surprise if subterranean Martian organisms were producing oxygen seasonally. Since the discovery of gigantic volumes of live biota in the Earth’s crust, the idea of active organic chemistry underground is well accepted. Does Mars have a big biosphere underground? It’s quite plausible, and many scientists consider it a very good working theory. However – The type of organism is a very interesting point when it comes to oxygen production. On Earth, things like algae produce a lot of oxygen. If Martian algae or the equivalent exist, and are responsible for the changing oxygen levels, these organisms could be a great clue for sourcing oxygen on Mars for manned missions. Inorganically derived oxygen? If the oxygen is inorganic, and seasonally triggered by temperature variations of environmental chemistry or some other process, it’s a new ballgame. Oxides like rocks are pretty tough. Breaking oxygen bonds to release free oxygen isn’t that easy. This inorganic process, if that’s what’s happening, could be invaluable for making oxygen on Mars. Such a process, however, could be pretty complex, working with unknown compounds and chemical processes. Free oxygen production at very low temperatures? Even more intriguing, especially given the cold environment on Mars, is the fact that this oxygen is being produced at extremely low temperatures. Low temperatures typically don’t encourage the release of oxygen on Earth. For example - Water ice has a lot of oxygen, and when it’s frozen, it stays frozen until it receives enough heat to evaporate. So- What’s happening on Mars? Is it a different type of oxygen bond, more fragile? Or are some incredibly hardy organisms waking up and pumping it out? Or both? It’s not totally unpredictable that ancient organisms could be very oxygen-efficient. They’d have to be. Maybe the organisms process inorganic materials to release the oxygen. That, at least, would be easily comprehensible, and much easier to work with to source oxygen on Mars. 

 

 

Paul Wallis

 

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