Did A Weak Magnetic Field 600 Million Years Ago Trigger The Emergence Of Animals?

Eddie Gonzales Jr. – MessageToEagle.com – During the Ediacaran Period, spanning from about 635 to 541 million years ago, the Earth’s environment underwent significant changes that led to the emergence of complex, multicellular organisms, paving the way for the subsequent explosion of life forms.

Understanding the unfolding of this surge in biodiversity and the potential contributing factors is crucial for comprehending the evolution of life on our planet.

Earth’s magnetic field. Credit: Adobe Stock – Pixel Matrix

Researchers from the University of Rochester have uncovered evidence suggesting that a weak magnetic field millions of years ago may have contributed to the proliferation of life. According to the scientists, this occurred during the Ediacaran Period when Earth’s magnetic field was in an unusual state, coinciding with the diversification and thriving of macroscopic animals.

Their study, published in Nature Communications Earth & Environment, raises the intriguing question of whether these fluctuations in Earth’s ancient magnetic field led to shifts in oxygen levels, which may have been crucial for the proliferation of life forms millions of years ago. The research team’s findings shed light on a potential link between Earth’s magnetic field dynamics and the evolution of life on our planet.

Animal magnetism? University of Rochester researchers studied Earth’s magnetic field during the transformative Ediacaran Period, which spanned from about 635 to 541 million years ago. The research raises questions about factors that may have fueled the emergence of complex, multicellular organisms, such as Ediacaran fauna, notable for their resemblance to early animals. (University of Rochester illustration / Michael Osadciw)

The Ediacaran Period witnessed the emergence of remarkable life forms known as the Ediacaran fauna. According to John Tarduno, the William Kenan, Jr. Professor in the Department of Earth and Environmental Sciences, these organisms were notable for their resemblance to early animals. Some of them even attained impressive sizes exceeding a meter (three feet) and exhibited mobility, suggesting a higher oxygen requirement compared to earlier life forms.

The Ediacaran Period witnessed the emergence of remarkable life forms known as the Ediacaran fauna. According to John Tarduno, the William Kenan, Jr. Professor in the Department of Earth and Environmental Sciences, these organisms were notable for their resemblance to early animals. Some even attained impressive sizes exceeding a meter (three feet) and exhibited mobility, suggesting a higher oxygen requirement than earlier life forms. This evidence sheds light on the evolutionary progression during this pivotal era, marking a significant step towards the diversification of life on Earth.

“Previous ideas for the appearance of the spectacular Ediacaran fauna have included genetic or ecologic driving factors, but the close timing with the ultra-low geomagnetic field motivated us to revisit environmental issues, and, in particular, atmospheric and ocean oxygenation,” says Tarduno, who is also the Dean of Research in the School of Arts & Sciences and the School of Engineering and Applied Sciences.

Earth’s Magnetic Mysteries

Earth’s magnetic field, generated by the churning of liquid iron in the planet’s outer core approximately 1,800 miles beneath our feet, plays a crucial role in sustaining life on our planet. This invisible force field acts as a protective shield, safeguarding Earth from the harmful solar wind – streams of radiation emanating from the sun. However, it is important to note that Earth’s magnetic field has not always been as robust as it is today.

Window on the past: Fossil impression of Dickinsonia, an example of Ediacaran fauna, found in present-day Australia. (Credit: Shuhai Xiao, Virginia Tech)

Researchers have put forth the hypothesis that an unusually weak magnetic field might have facilitated the emergence and evolution of animal life on Earth. Unfortunately, establishing a definitive link between these two phenomena has proven challenging due to the limited availability of data regarding the strength of the magnetic field during the relevant time period.

Tarduno and his team used innovative strategies and techniques to examine the strength of the magnetic field by studying magnetism locked in ancient feldspar and pyroxene crystals from the rock anorthosite. The crystals contain magnetic particles that preserve magnetization from the time the minerals were formed. By dating the rocks, researchers can construct a timeline of the development of Earth’s magnetic field.

Leveraging cutting-edge tools, including a CO₂ laser and the lab’s superconducting quantum interference device (SQUID) magnetometer, the team precisely analyzed the crystals and the magnetism locked within.

A Weak Magnetic Field

Earth’s magnetic field plays a crucial role in shielding our planet from harmful solar radiation. Recent data analysis suggests that during the Ediacaran Period, approximately 635 to 541 million years ago, the magnetic field experienced an unprecedented weakening. The field strength was up to 30 times weaker than the current magnetic field, and this ultra-low intensity persisted for at least 26 million years.

A weak magnetic field facilitates the stripping away of lightweight atoms, such as hydrogen, from the atmosphere by charged particles from the sun. This process, known as atmospheric escape, can lead to a significant loss of hydrogen. When hydrogen is depleted, more oxygen remains in the atmosphere instead of reacting with hydrogen to form water vapor. These reactions can potentially result in an accumulation of oxygen over an extended period.

The research conducted by Tarduno and his team provides valuable insights into the Earth’s ancient magnetic field and its potential impact on the evolution of life. Their findings suggest that the Earth’s magnetic field was extremely weak during the Ediacaran Period, approximately 635 to 541 million years ago. This ultraweak magnetic field is believed to have caused a significant loss of hydrogen from the atmosphere over tens of millions of years. This hydrogen loss may have led to an increased oxygenation of the atmosphere and surface ocean, creating an environment more conducive to the emergence of more complex life forms.

Additionally, Tarduno and his team had previously discovered that the geomagnetic field regained its strength during the subsequent Cambrian Period, which spanned from approximately 541 to 485 million years ago. This period is notable for the appearance of most major animal groups in the fossil record. The re-establishment of a protective magnetic field during this time is thought to have allowed life to thrive and diversify.

Hard copy: Fossil impression of Fractofusus, an example of Ediacaran fauna, found in what is now Newfoundland, with a Canadian penny nearby for scale. (Credit: Shuhai Xiao, Virginia Tech)

“If the extraordinarily weak field had remained after the Ediacaran, Earth might look very different from the water-rich planet it is today: water loss might have gradually dried Earth,” Tarduno says.

The study highlights the importance of understanding planetary interiors when considering the potential for life beyond Earth.

In a press release, Tarduno states, “It’s fascinating to think that processes in Earth’s core could be linked ultimately to evolution.” He further emphasizes, “As we think about the possibility of life elsewhere, we also need to consider how the interiors of planets form and develop.”

This research was supported by the US National Science Foundation.

Written by Eddie Gonzales Jr. – MessageToEagle.com Staff