Researchers in have discovered ancient, extremophile life forms that survive with neither light nor oxygen underground in Antarctica.
From the surface, the McMurdo Dry Valleys of Eastern Antarctica appears to be one of the most desolate places on Earth. And indeed it is. Apart from a few glaciers, the land is ice-free. No animals live here, and what few plants are able to are simple planktonic forms. But recently, a team of researchers have discovered evidence of a thriving community of extremophile microbes thriving several hundred feet below the barren surface.
The evidence came in the form of an outpouring of meltwater from the base of Taylor Glacier, one of the outlet glaciers of the vast East Antarctic Ice Sheet. The samples were collected from a feature known aptly as Blood Falls, due to the rust-red coloration of briny effluent that occasionally issues from it. The source of this effluent is believed to be a 3 mile diameter, high-salinity “pool” (which doesn’t freeze due to the salt content) buried inland and deep under the glacier.
The results of sample analyses revealed an abundance of microbial life similar to some present day oceanic and land microbes, but also quite different in key ways-they are capable of reproducing in the complete absence of either light or oxygen. These microbes are in some ways closer to Archaea, a branch of simple unicellular organisms believed to be amongst the most ancient microbial forms to appear on earth.
There has been much debate amongst paleo-biologists concerning which environment–the warm, sunny, oxygenated, clay-rich tidal pools of the seashore, or, the aphototic, hydrogen sulfide-spewing, thermal vents of the deep sea–was first to give rise to simple, unicellular creatures. With the discovery of these sub glacial microbes-thriving in the absence of both light and oxygen, and thermal venting, the mystery has now grown deeper.
The microbial community is believed to have been in existence for at least 1.5 million years, and probably longer, based upon dating of the surrounding geology and the comparison of the microbes genes with other known species.
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