Could happen again to Snowball Earth

"Snowball Earth" could have become the giver of life

Canberra - In the final stages of the so-called Proterozoic - an era that began 2.5 billion years ago and ended 541 million years ago - the earth was plunged into an extreme cold and warm rollercoaster. In the penultimate section, the cryogenium 850 to 635 million years ago, the earth froze several times to an extent that had never happened before and that even exceeded the most recent ice age by orders of magnitude.

This phase became popular under the slogan "Snowball Earth", even if there was probably never an icing from pole to pole. It is more likely that even in times of extreme glaciation there were ice-free places where the old life could survive. Scientists today are more likely to assume a "mud ball earth".

The new paradise

These mega-ice ages were followed by the cozy, warm age of the Ediacarium, in which life exploded and new forms emerged. The first large and complex organisms spread in the seas, which had been dominated by bacteria until then.

Australian researchers now believe that they have found the solution to how life on earth could have such an upswing just after the greatest climate catastrophe in the history of the earth. Algae made it possible, reports a team led by Jochen Brocks from the Australian National University in the specialist magazine "Nature".

The researchers examined sedimentary rock from the interior of Australia, which dates from the period in question, and found evidence of a primeval fertilization mechanism. The huge glaciers that weighed on the continents during the snow or mud ball age pulverized entire mountain ranges to powder. Huge amounts of minerals were released, which ultimately ended up in the oceans.

As the global climate warmed up, these minerals served as nutrients for algae, which allowed them to spread in unprecedented ways. And these algae in turn became the basis of food for other organisms, which enabled more complex ecosystems to develop for the first time. According to Brocks, it was ultimately the same glaciation of the earth that initially delayed the development of life for a long time, which then provided the energy for life to climb to a whole new level of complexity. (jdo, August 20, 2017)