A team of researchers has made a remarkable discovery: they’ve analyzed ancient air bubbles found in 1.4-billion-year-old salt crystals from northern Ontario, Canada. This breakthrough offers the first clear look at atmospheric oxygen and carbon dioxide levels from the Mesoproterozoic era.
For years, scientists worked to extract gas samples from halite crystals that hold remnants of Earth’s early atmosphere. This effort is changing our understanding of the Mesoproterozoic period, often dubbed the “Boring Billion” due to its perceived lack of evolutionary change.
The Mesoproterozoic era, which spanned from 1.8 to 0.8 billion years ago, was previously thought to be stagnant in terms of geological and biological evolution. Yet this research reveals that the atmosphere was actually undergoing significant transformations, even if the overall oxygen levels were relatively low. Earlier estimates relied on indirect measurements, leaving considerable gaps in our knowledge.
The findings, shared in the Proceedings of the National Academy of Sciences, show that oxygen levels were about 3.7% of what they are today. Surprisingly, the carbon dioxide levels were ten times higher than preindustrial levels, suggesting a warmer climate than previously believed.
Measuring ancient gases poses unique challenges. Halite crystals, which contain air bubbles and brine, make extracting accurate gas readings difficult. According to Professor Morgan Schaller, the lead researcher, “The carbon dioxide measurements we obtained have never been done before. These are actual samples of ancient air!”
The team managed to isolate and analyze these air bubbles, uncovering information about a climate more temperate than expected. This challenges past theories that depicted the Mesoproterozoic era as cooler and less stable. Professor Schaller noted that red algae appeared during this time and continue to play a vital role in global oxygen production.
Interestingly, researchers suggest that the relatively high oxygen levels during this period may be linked to the rise of complex algal life, which could have been essential for sustaining life when the Sun was weaker.
This study not only sheds light on our planet’s history but also hints at how ancient atmospheric conditions might influence today’s climate debates. Understanding the past equips us to tackle present-day challenges in environmental science.
For more on this fascinating topic, you can read the full study in the Proceedings of the National Academy of Sciences here.
