Weak Ediacaran magnetic field may have boosted complex life

The emergence and diversification of multicellular organisms on Earth appears to have coincided with the weakest magnetic field in Earth's history, which suggests a direct correlation. This has been determined by an international research group, as the University of Rochester in the US state of New York has now announced. Extensive analysis of ancient silicate rocks indicates Earth's magnetic field was up to 30 times weaker during the Ediacaran period, around 600 million years ago. This significant weakening lasted for several tens of millions of years. This could have contributed to the enrichment of the atmosphere with oxygen, and thus enabled the development of advanced life forms in the first place.

Not too short, not too long

As the university summarizes, an enormous variety of multicellular organisms appeared on Earth in the Ediacarium. The so-called Ediacara fauna is particularly well known, with specimens up to one meter long, some of which could even have been mobile. It has therefore long been assumed that they needed more oxygen. However, genetic factors and favorable environmental conditions have also been proposed as the cause of their emergence. However, the analysis of silicate crystals using state-of-the-art tools has now revealed a direct temporal link to a particularly weak geomagnetic field.

Such a weakened Earth's magnetic field could have enabled charged solar particles to knock hydrogen out of atoms, the university summarizes the hypothesis. The hydrogen particles could then have escaped from the atmosphere, which may have led to the remaining oxygen accumulating there. This increase in oxygen in the atmosphere and water would therefore be the basis for the emergence of multicellular organisms. At the same time, however, the research group also writes that the subsequent strengthening of the magnetic field probably protected the resulting life. Otherwise, our home would most likely not have been able to hold all the water on its surface and the Earth would have dried out.

It is fascinating to think about how processes in the Earth's interior are linked to the origin and development of life, says physicist John Tarduno, explaining the significance of the study. Just a few days ago, another research group revealed that the Earth's magnetic field is probably older than previously thought. This has also suggested a link to the origin of life. Both studies clearly show how many factors evolution on Earth was and is dependent on. This also has implications for the search for extraterrestrial life, says Tarduno. Processes in the interior of exoplanets must be included in the search. The study has been published in the journal Nature Communications Earth & Environment.

(mho)