New Mars Forums

Void

Member

Registered: 2011-12-29

Posts: 7,819

Lake Vida

Lake Vida in Antarctica.

-13 degC water (8 degF)

5-6 times saltier than the ocean

No Oxygen

1/10 as much bacteria as a fresh water lake, somehow.

Brine Channels.

It just looks rather interesting to me.

http://www.livescience.com/25032-ancien … found.html
http://www.daviddarling.info/encycloped … eVida.html
https://en.wikipedia.org/wiki/Lake_Vida
http://www.nature.com/news/life-abounds … ce-1.11884

It is permanently covered by a massive cap of ice up to 27 metres thick, is six times saltier than normal sea water, and at −13 °C is one of the coldest aquatic environments on Earth — yet Lake Vida in Antarctica teems with life.

Exotic energy sources

The team has not yet worked out how the bacteria produce energy. They might emulate many known bacteria by living solely on dissolved organic carbon; or they might use more exotic forms of energy, as do some other microbes living in extreme environments. For example, bacteria in deep gold mines are known to survive on molecular hydrogen produced by chemical reactions in the rocks.

“For sure, there is a lot of energy in the brine,” says Murray. “Carbon may be the primary energy source, but hydrogen may be vital to sustain the lake’s microbial life in the long-term.”

The ice cap over the lake grows upwards as melt water from surrounding glaciers flows over the ice and refreezes. Isotope analysis of organic carbon particles in the ice suggests that the lake has been sealed for around 2,800 years, so any carbon in the brine must have been there for at least that long and there probably isn't very much of it — suggesting that the microbes may be using something else to produce energy.

Because they are isolated and there are no predators in the lake, says Murray, the cells might have switched to a biologically reduced ‘survival mode’ — without cell division and reproduction — that allows them to endure stress and harsh environments for a long time.

I will do some speculating.  The brine should eat its way upwards through the fresh water ice, extending brine channels.  Although the ice is very thick, and light may not get into the waters itself very much, the brine channels may extend upwards and who knows may encounter sufficient photons for photosynthesis.

I recently have read of an ancient form of photosynthesis which exists still, in a bay in a lake in Africa.  It Oxidizes Iron, and produces Hydrogen, not Oxygen. 

I could be quite wrong (easily), but I speculate that in the brine channels of the ice of this lake could be such organisms producing the Hydrogen found, driving the life system to some extent.

I reserve the right to be wrong sometimes, but we will see.  This would be very exciting to me.

I have speculated on dry valley lakes of this kind, but of a very much larger size, such as the size of the Caspian sea, on alien planets.  Cold alien planets.  I have speculated that even without running fresh water, it might be possible for such bodies of water to be hydrated, by glaciers flowing into them, and encountering waters sufficiently salty and warm to melt fresh water.  So, I say that by this method a photo driven biology could be sustained on worlds outside the outer limits of the traditional habitable zone.  Maybe not that far out.  A difference on such speculative worlds also is that such lakes in those cases could be on the equator of such worlds, and so sunlight/starlight, would come from overhead more and not as sideways as in the case of Lake Vida.  This would of course allow for a deeper penetration of the ice, and the meeting of photons with liquid in brine channels in ice.

Also on those worlds where fresh water never melts, a coating of fresh water ice would not be deposited on the surface of the ice, and this would make it very likely that brine channels could rise in the ice perhaps nearly to the surface of the ice.  Those brine channels could warm up periodically when the sun is at it's summer solstice.

More speculation, but I like it.

Last edited by Void (2015-09-10 21:43:03)

---

End