If there is life in the lakes under the ice of Antarctica then how can those bacteria survive? Where do they get energy from?


The dark waters of a lake deep beneath the West Antarctic ice sheet and a few hundred miles from the South Pole are teeming with bacterial life, say scientists — despite it being one of the most extreme environments on Earth.

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    $\begingroup$ Welcome to SE.biology! It's expected that you show some evidence that you've tried to research the question before posting here. Please take a read of the help centre section on how to ask a good question and consider editing your post. $\endgroup$ – user438383 Sep 30 at 8:56
  • $\begingroup$ I quoted a link now. Is that enough? $\endgroup$ – Joe Jobs Oct 1 at 10:25
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    $\begingroup$ @JoeJobs The article you linked says "Scientists theorize that the bacteria in Lake Whillans — and possibly Lake Mercer — are surviving on deposits of carbon laid down by photosynthesizing organisms between 5000 and 10,000 years ago, when the buried lakes may have been connected to the open ocean." Can you explain where your question remains? $\endgroup$ – Bryan Krause Oct 1 at 15:03

I knew Priscu and worked with some of his grad students at Montana State.

Here's one of their papers on the Lake Whillans project.

One of the more relevant findings is that many of the most abundant organisms (by genetic analysis of small subunit ribosomal RNA genes) were closely related to chemolithoautotrophic organisms. Basically, organisms that can obtain energy by oxidizing inorganic compounds. They found that there was sufficient chemolithoautotrophic carbon incorporation to support the heterotrophic demands of the ecosystem. They also found an abundance of organisms related to nitrifiers (organisms that oxidize ammonia into nitrite and nitrate), along with sufficient ammonia, suggesting that nitrification is a primary pathway of new organic carbon production in the ecosystem.

Source: Christner, Brent C., et al. "A microbial ecosystem beneath the West Antarctic ice sheet." Nature 512.7514 (2014): 310-313.

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  • $\begingroup$ How can oxidation of ammonia produce carbon? $\endgroup$ – Joe Jobs Oct 1 at 19:47
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    $\begingroup$ Good question (guess I skipped over that part). The source of new carbon for most autotrophs is $\mathrm{CO_2}$. To my knowledge all nitrifiers fix $\mathrm{CO_2}$ using the Calvin Cycle, which is the same pathway used by by plants and most photosynthetic bacteria (photoautotrophs). The only differences is where the energy comes from. Photoautotrophs use light, and chemoautotrophs use chemicals. There are other carbon fixation pathways used by other organism as well. $\endgroup$ – MikeyC Oct 1 at 20:28
  • $\begingroup$ BTW. I did not just have all that knowledge at the ready. I flipped open my copy of "The Physiology and Biochemistry of Prokaryotes" that I keep on my desk at work (By White, Drummond, & Fuqua). An excellent reference if you're interested in bacterial physiology. $\endgroup$ – MikeyC Oct 1 at 20:34

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