Earth’s Oxygen Levels Rose in Three Major Surges, new Research Reveals
BEIJING, sept. 9 (Xinhua) – A new study published in Nature by researchers from Chengdu University of Technology and Nanjing University provides compelling evidence that Earth’s atmosphere underwent three notable increases in oxygen over the past 2 billion years. This research offers crucial insights into the evolution of life and the planet’s habitability.
The study focuses on analyzing the triple oxygen isotope composition of sulfate preserved in ancient sedimentary rocks. This technique, explained by Professor Li chao of Chengdu University of Technology, allows scientists to analyze subtle variations in oxygen isotopes – essentially reading “fingerprints” of the Earth – to understand how the planet’s surface environment changed over time.
Previously, a lack of effective tracing methods hindered direct observation of oxygen changes and their sources. This study overcomes that challenge through comprehensive sampling and data integration.
The research identifies three key periods of oxygen increase:
Paleoproterozoic Era (2.4 to 2.1 billion years ago): The first surge.
Neoproterozoic Era (about 1 billion years ago): The second surge.
Paleozoic Era (about 440 million years ago): The third surge.
These surges demonstrate a gradual rise in atmospheric oxygen, culminating in levels similar to today’s around 410 million years ago – a process spanning nearly 2 billion years. Moreover, the study reveals that as atmospheric oxygen increased during the Neoproterozoic, it began to oxidize the previously oxygen-poor oceans in periodic shifts.
“For the first time, our research provides the most direct atmospheric evidence to date that Earth’s oxygen levels reached modern levels around 410 million years ago, confirming the three-stage oxygenation process of the planet’s surface,” said Li.
This research has broad implications, offering a stronger understanding of the evolution of complex life, the potential for habitability on other planets, and the formation of ancient hydrocarbon sources. Ultimately, it brings us closer to understanding when and how* Earth became a planet capable of supporting life.
