The Ediacaran period, which lasted from approximately 635 million years ago to 541 million years ago, was a very important period in Earth history. This marked a transformative period in which complex multicellular organisms emerged that formed the basis for the explosion of life.
So how did this explosion of life happen, and what factors on Earth might have contributed to it?
Researchers at the University of Rochester have found compelling evidence that the Earth’s magnetic field was in a very unusual state as macroscopic animals of the Ediacaran period diversified and evolved. Research published in the journal Nature Communication Soil and EnvironmentIt raises the question of whether these fluctuations in Earth’s ancient magnetic field led to changes in oxygen levels that would have been crucial for the spread of life forms millions of years ago.
According to John Tarduno, William Kenan Professor of Earth and Environmental Sciences, one of the most distinctive life forms of the Ediacaran period was the Ediacaran fauna. They differed in their resemblance to the first animals; Some even reached more than one meter (three feet) in size and were mobile; This showed that they needed more oxygen than previous life forms.
“Previous ideas about the emergence of the magnificent Ediacaran fauna involved genetic or environmental driving factors, but the recent ultra-low geomagnetic field has led us to rethink environmental concerns, particularly atmospheric and ocean oxygenation,” says Tarduno. He also serves as dean of science at the Faculty of Arts and Sciences and the School of Engineering and Applied Sciences.
Earth’s magnetic secrets
About 4,800 miles below us, liquid iron is spreading through the Earth’s outer core, creating the planet’s protective magnetic field. Although the magnetic field is invisible, it is important to life on Earth because it protects the planet from the solar wind and radiation streams from the Sun. But the Earth’s magnetic field wasn’t always as strong as it is today.
The researchers suggested that the extremely low magnetic field may have contributed to the animals’ appearance. However, it was difficult to confirm the connection because data on the strength of the magnetic field was limited during this time.
Tarduno and his team used innovative strategies and methods to study magnetic field strength by examining magnetism recorded in pyroxene crystals in ancient feldspar and anorthosite. Crystals contain magnetic particles that maintain magnetization from the moment the minerals are formed. By dating rocks, researchers can establish the chronology of the development of the Earth’s magnetic field.
Using state-of-the-art tools, including CO2- laser and using the lab’s Superconducting Quantum Interference Device (SQUID) magnetometer, the team precisely analyzed the crystals and the magnetism locked inside.
weak magnetic field
Their data show that during the Ediacaran period the Earth’s magnetic field was the weakest known today (30 times weaker than today’s magnetic field) and that the ultra-low field strength lasted for at least 26 million years.
The weak magnetic field makes it easier for charged particles from the Sun to pluck light atoms such as hydrogen from the atmosphere and launch them into space. If hydrogen loss is significant, more oxygen may remain in the atmosphere instead of reacting with hydrogen to form water vapor. These reactions can lead to oxygen accumulation over time.
Tarduno and his team’s work suggests that an ultra-weak magnetic field during the Ediacaran period caused hydrogen loss over at least tens of millions of years. This loss may have led to increased oxygenation of the atmosphere and ocean surface and the emergence of more advanced life forms.
Tarduno and his research team had previously found that the geomagnetic field improved and the protective magnetic field revived during the Cambrian period, when most animal groups began to appear in the fossil record, allowing life to flourish.
“If an extremely weak field had remained after the Ediacaran, Earth might have looked very different from the water-rich planet it is today: water loss could have slowly dried the Earth,” says Tarduno.
Basic dynamics and evolution
The study suggests that understanding the interiors of planets is critical to envisioning the potential for life beyond Earth.
“It’s a fascinating idea that processes in the Earth’s core may be related to evolution,” says Tarduno. “When we consider the possibility of life elsewhere, we also need to consider how inner planets form and evolve.” To learn more about this study, see How did Earth’s weak magnetic field contribute to the emergence of complex life?
Source: Port Altele
