According to a news release from the University of British Columbia, the Earth had oxygen much earlier than previously thought. In fact, oxygen may have emerged up to 700 million years earlier. The findings raise new quesitons about the evolution of early life, as oxygen is a gaseous chemical element on which most organisms depend.

Researchers from the University of Copenhagen and University of British Columbia analyzed the chemical makeup of three-billion-year-old soil originating from South Africa (these are the most ancient soils on our planet) and discovered evidence for low concentrations of atmospheric oxygen.

Earlier research revealed that oxygen started collecting in the atmosphere only approximately 2.3 billion years ago during an active time in Earth’s history known as the Great Oxygenation Event.

“We’ve always known that oxygen production by photosynthesis led to the eventual oxygenation of the atmosphere and the evolution of aerobic life,” said Sean Crowe, an assistant professor in the Departments of Microbiology and Immunology, and Earth, Ocean and Atmospheric Sciences at the University of British Columbia, in a statement.

“This study now suggests that the process began very early in Earth’s history, supporting a much greater antiquity for oxygen producing photosynthesis and aerobic life,” Crowe added.

There was a lack of oxygen in the atmosphere for at least hundreds of millions of years after the Earth came into being. Today, our planet’s atmosphere is 20 percent oxygen due to photosynthetic bacteria that feed on carbon dioxide and give off oxygen. According to researchers, the bacteria enabled oxygen-requiring organisms to develop and live on Earth.

“These findings imply that it took a very long time for geological and biological processes to conspire and produce the oxygen rich atmosphere we now enjoy,” noted Lasse Døssin from the University of Copenhagen.

The study’s findings are discussed in greater detail in the journal Nature.