Did volcanoes spark the rise of oxygen on Earth? Scientists find groundbreaking evidence

For billions of years, the atmosphere on Earth was nothing like it is now—no oxygen, no air to breathe, just a barren wasteland shrouded in mystery. And then something shifted. Scientists have long argued over what caused the oxygenation, setting the stage for life as we know it. A new study suggests that volcanoes might have had a much larger role than anyone ever imagined. By studying ancient rock fossils, scientists have made intriguing discoveries that may redefine the history of Earth's earliest moments. Did explosive eruptions secretly power the very air we breathe? The new find may be the key.

Prior to Earth's enrichment with oxygen, its atmosphere was quite different from what we inhale now. To know about these ancient conditions, scientists examined stromatolites—layered rock formations created by Cyanobacteria billions of years ago. These fossils hold the history of nitrogen cycling, a vital process for life. Scientists examined nitrogen isotopes trapped in Zimbabwe's ancient stromatolites, revealing how nitrogen was transformed into forms usable by early organisms.
Nitrogen, as phosphorus, is fundamental to biological productivity in oceans, and its study is therefore paramount to understanding early life evolution. Scientists discovered that deep-sea nitrogen was mostly present in the ammonium form, which was instrumental in supporting primitive life. This finding gives fresh insight into how vital nutrients sustained early microbial communities prior to oxygen-producing photosynthesis. By concentrating on the role of nitrogen instead of oxygen, researchers are illuminating Earth's pre-oxygen atmosphere in new ways.

Volcanoes were important in the formation of early life on Earth, well before the Earth had oxygenated air. Scientists have been mystified by strange nitrogen isotope signatures in ancient stromatolites for a long time. New research indicates that volcanic activity played a role in nutrient recycling, supporting early microbes. With little oxygen in the early oceans, volcanic eruptions deposited minerals and nutrients into the ocean, providing a perfect environment for microbial growth. These microorganisms, in turn, led to the gradual accumulation of oxygen over a long period.
Another important result from this study, which appears in Nature Communications, is that volcanic activity offered a constant supply of nitrogen and other nutrients that are vital to life. This cycle could have supported the biological alterations that eventually led to photosynthesis that produced oxygen. By revealing the connection between microbes and volcanoes, researchers are learning new insights into the driving forces behind Earth's evolutionary history.
Also Read: Space missions that ended in disaster and changed history