THE SCIENCE TIMES - To understand how life came to be, it is important to note the atmospheric history of the planet, which allowed life to succeed. One of the important events in atmospheric history is the Great Oxidation Event, wherein the Earth's shallow oceans experienced a dramatic increase in oxygen. Millions of years, later the planet experienced a drop in oxygen in the atmosphere, and this was called the Lomagundi event, the most prominent carbon isotope event in the planet's atmospheric history. The causes of the said oxidation events were unclear until recently.
The researchers would like to focus on carbon isotopes in explaining these events. Since carbon has three naturally-occurring isotopes (variants can be determined based on the number of neutrons), the ratio of carbon-12 and carbon-13 isotopes becomes a useful tool for studying natural systems, especially in the atmosphere. This is because carbon-12 and carbon-13 come from different sources. Geoscientist James Eguchi from the University of California Riverside explains, "what makes this unique is that it's not just trying to explain the rise of oxygen. It is also trying to explain some closely associated surface geochemistry, a change in the composition of carbon isotopes that are observed in the carbonate rock record shortly after the oxidation event."