14 DAY TRIAL // The conclusions of a new scientific study indicate that our planet's atmosphere oscillated between a hydrocarbon-free and a hydrocarbon-rich state some 2.5 billion years ago, before the Great Oxygenation Event occurred.
This phenomenon saw the release of vast amounts of oxygen in the atmosphere, and ultimately allowed complex lifeforms – including ourselves – to emerge and evolve. Before that time, the atmosphere exhibited impressive fluctuations, from hazy to clear.
According to some astronomers, Earth's gaseous layer may have looked like that surrounding Titan, Saturn's largest moon. The image to the left shows a natural-color image of how the celestial body looks like at this point.
The new investigation was conducted by researchers at the Newcastle University, in the United Kingdom. Details of the work appear in the March 21 issue of the top journal Nature Geoscience.
These alternating, organic haze and haze-free environments were triggered by the most unlikely sources – microbes. Intense activity in the huge colonies these microorganisms formed at the time had a direct and profound influence on the planet's climate.
“Models have previously suggested that the Earth's early atmosphere could have been warmed by a layer of organic haze. Our geochemical analyses of marine sediments from this time period provide the first evidence for such an atmosphere,” Dr. Aubrey Zerkle explains.
The expert, who holds an appointment with the School of Civil Engineering and Geosciences at the university, was the lead author of the investigation. Studies such as this could also provide us with insight into how Earth's surface environment looked like before the GOE.
“However, instead of evidence for a continuously 'hazy' period we found the signal flipped on and off, in response to microbial activity. "This provides us with insight into Earth's surface environment prior to oxygenation of the planet and confirms the importance of methane gas in regulating the early atmosphere,” the team leader adds.
In the future, scientists plan to use these results to draw a series of conclusions about how aerosols, particularly those of the organic nature, appeared in Earth's atmosphere, Astrobiology Magazine reports.