Hundred-thousand-year-old frozen microorganisms revived after thawing
Antarctica’s glaciers contain the oldest ice in the world. Scientists estimate the age at up to eight million years. Because the ice in antarctica is exposed to stronger cosmic rays than anywhere else on earth, researchers aren’t the only ones eagerly watching to see what’s trapped in the ice and what happens to the objects in the world’s oldest freezer when they thaw out.
Filmmakers early ventured a glimpse into the alien world and found the uncanny: seemingly dead life awakened from eternal rigidity by man’s curiosity and revealed to be a thing-creature that man cannot control.
Life that was frozen in the antarctic ice and once thawed resumes its activities was also discovered by american scientists who now present their work to the public in the scientific journal pnas::"locked in glaciers, ancient ice may return to life as glaciers melt".
What kay bidle, professor of marine and coastal sciences at rutgers university, and his colleagues at the korea polar research institute and boston university found in thawed samples from five ice samples aged between 100.000 and eight million years ago is not quite as scary as the "thing" from howard hawks. The imagination, however, can be preoccupied by what researchers discovered in the five blocks of ice that boston university glaciologist dave marchant cut out of the transantarctic mountains and sent to bidle et. Al. Has sent.
What in scientific jargon is called "significant" can even be considered spectacular: until the present work of bidle et al. It was not clear that old, frozen organisms could be revived and that frozen cells were viable, according to bidle, who led the study.
They are, up to a certain age even very. In fact – and even this was not certain for bidle – the researchers found microorganisms in the antarctic ice blocks, especially in the younger ones, which love to revive easily: in suitable environments, the microorganisms from the younger ice grew rapidly, doubling in size every few days. In contrast, microorganisms from the oldest ice reproduced only very slowly, every 70 days.
"Exponential decay" of dna after 1.1 million years
When these microorganisms grew, they were no longer recognizable. Reason: their dna was no longer intact. The comparison of the dna in the five different samples showed an "exponential decay" after 1.1 million years. Dna is still there after this time, but, according to bidle, only half of it. Every 1.1 million years the dna was statistically split in half. The average coarseness of the dna from the old ice was 210 base pairs. For comparison: the average size of a bacterial genome is 3 million base pairs.
According to scientists, the destruction of dna is caused by cosmic radiation affecting the anatarctic glaciers. In geological periods it was splitting dna into pieces and most organisms could not repair this damage. Because dna is so destroyed by cosmic rays in ancient ice, researchers conclude that life on earth could not have been brought here by a comet or other cosmic object outside the solar system. While it was possible that microbes and their genes could be transported between planets in icy comets, the extremely high cosmic rays in space made it unlikely that genetic material from outside the solar system could seed life on earth, according to available results.