The recent discovery of liquid, highly saline, water on Mars has the scientific community aflutter about the possibility of life on the red planet. It’s an exciting prospect, don’t get me wrong, but I don’t think Marvin the Martian is going to be knocking on our door anytime soon, or well… ever. If life exists on Mars, I suspect it’s going to be in a very unglamorous form.
A few years ago I did a 6 week solo birding and photography trip through Bolivia. One of my excursions was a week spent touring the high desert altiplano in the southwestern corner of the country. It’s a crazy place full of crazy stuff. The extreme elevation (13,000-15,000 feet) ads a mental dizziness to its weirdness. No part of the altiplano however, is stranger than the Salar de Uyuni.
Covering more than 4000 square miles the Salar is the world’s largest salt flat. Though it lies in one of the driest places on the planet, the rare rains, few springs, and one seasonal river (which flows into the Salar but not out) creates a shallow layer of water which blows around the surface of the Salar, alternately leaving some areas covered in a foot of saline water while other areas bake dry in the desert sun.
If you encounter the Salar where it’s covered in water, the weirdness turns surreal. I was there for sunrise on a nearly windless morning and the reflections were so perfect, it was impossible to tell up from down. It was bizarre and dizzying and wonderful.
But the birding wasn’t that great. In fact, the Salar de Uyuni and the similar salt flats elsewhere in Bolivia and neighboring Chile are almost entirely vacant of life. The water, is thickly saline, holding close to the total salt volume possible. And thick it is, in the hand, it feels slippery, almost gooey, more gel than liquid. This consistency, and the constant evaporation and recharge makes aquatic life impossible. Or nearly impossible anyway. As far as I could determine after doing some literature searches, the biggest creatures to make a permanent home in the Salar de Uyuni are bacteria. And there aren’t that many of them. Anything that manages to survive under such extreme conditions has to tolerate maximum concentrations of salt and other chemicals, be able to handle periodic drying, intense UV rays from the high-elevation, desert sun, and of course, survive in the relatively thin atmosphere of the altiplano.
Which brings me back to Mars. If life in the Salar de Uyuni is hard, or nearly impossible, what must it be like on Mars? The thin atmosphere of Mars (approx 1/100th density of Earth) makes the air of the altiplano seem positively muggy. UV Rays? Mars’ thin atmosphere does little to protect from those. And then there is the highly saline water, already difficult, and the fact that the water survives above the surface for very short periods of time before evaporating or boiling off.
Life does occur in crazy places. From deep-ocean thermal vents to algae growing in frigid snow pack, to the Salar de Uyuni itself, life has found a way. But if life persists under the conditions on Mars… well that critter is one tough mo’ fo’.