Climate change and the rise of atmospheric oxygen

March 23, 2006

Today's climate change pales in comparison with what happened as Earth gave birth to its oxygen-containing atmosphere billions of years ago. By analyzing clues contained in rocks, scientists at the Carnegie Institution's Geophysical Laboratory have found that the initial rise of oxygen (O2) was transitory and that its final emergence may have been linked to volcanoes and catastrophic glaciations.

"Rocks contain fingerprint-like clues to the past environment through specific variations in elements such as sulfur," explained Carnegie researcher Shuhei Ono. "Our Earth didn't start out with oxygen in the atmosphere. It probably contained methane and hydrogen, but no oxygen. We think that there were microbes in the oceans, before the oxygenated atmosphere, which would have used methane for energy. Measuring sulfur isotopes--different versions of the atom with the same number of protons, but a different number of neutrons--in rock samples provides a sensitive way to monitor ancient oxygen levels. Oxygen first appeared on the surface of the Earth when microbes developed the capacity to split water molecules to produce O2 using the Sun's energy. This is a bit advanced biochemistry, but we think this biological revolution emerged sometime before 2.7 billion years ago," he continued.

Ono looked at sulfur isotopes from South African drill-core samples covering the time interval from 3.2 to 2.4 billion years ago. Around 2.9 billion years ago, the methane-dominated atmosphere provided a greenhouse effect and kept the planet warm. His analysis suggests that when oxygen first appeared in the atmosphere, around that time, it would have reacted with the methane, destabilizing the atmosphere and triggering the Mozaan-Witwatersrand glaciation.

The oxygen atmosphere wasn't here to stay, however. "It was a raucous time," stated Carnegie's Andrey Bekker. "Volcanoes peppered the Earth's surface, belching gases and particulates into the atmosphere. That material rained back to the surface and oceans, affecting ocean chemistry and the ocean and atmospheric cycles. We looked at sulfur isotopes in shale and pyrite from Western Australia and found that between 2.47 and 2.463 billion years ago oxygen levels started to rise. But the intense volcanic activity made it almost disappear again. Despite these fits and starts, our oxygen atmosphere prevailed in the end."

The work is presented in several talks at NASA's Astrobiology Science Conference (AbSciCon) 2006 in Washington, D.C., March 26-30. See http://abscicon2006.arc.nasa.gov/ for details.

Source: Carnegie Institution

Explore further: The gas giant Jupiter

Related Stories

The gas giant Jupiter

August 26, 2015

Ever since the invention of the telescope four hundred years ago, astronomers have been fascinated by the gas giant known as Jupiter. Between it's constant, swirling clouds, its many, many moons, and its red spot, there are ...

Earth's mineralogy unique in the cosmos

August 26, 2015

New research from a team led by Carnegie's Robert Hazen predicts that Earth has more than 1,500 undiscovered minerals and that the exact mineral diversity of our planet is unique and could not be duplicated anywhere in the ...

The planet Mercury

August 6, 2015

Mercury is the closest planet to our sun, the smallest of the eight planets, and one of the most extreme worlds in our solar systems. Named after the Roman messenger of the gods, the planet is one of a handful that can be ...

'Snowball earth' might be slushy

August 3, 2015

Imagine a world without liquid water—just solid ice in all directions. It would certainly not be a place that most life forms would like to live.

Recommended for you

New Horizons team selects potential Kuiper Belt flyby target

August 29, 2015

NASA has selected the potential next destination for the New Horizons mission to visit after its historic July 14 flyby of the Pluto system. The destination is a small Kuiper Belt object (KBO) known as 2014 MU69 that orbits ...

Seeing quantum motion

August 28, 2015

Consider the pendulum of a grandfather clock. If you forget to wind it, you will eventually find the pendulum at rest, unmoving. However, this simple observation is only valid at the level of classical physics—the laws ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

QubitTamer
3 / 5 (2) Apr 08, 2009
How DARE the earth change the climate without first consulting with the dominant species on the planet, the UN IPCC! I doubt the UN IPCC would have approved of the outrageous pumping of deadly gases like pure oxygen into the pristine and fragile atmosphere of the early earth.

I suggest an additional 25% across the board income, energy, and consumption tax on all U.S. citizens AND their pets and livestock who breathe oxygen as a retroactive penalty for benefiting from this horrible climate crime perpatrated only a scant few billion years ago.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.