Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hazy shades of life on early Earth

19.03.2012
A 'see-sawing' atmosphere over 2.5 billion years ago preceded the oxygenation of our planet and the development of complex life on Earth, a new study has shown.
Research, led by experts at Newcastle University, UK, and published today in the journal Nature Geoscience, reveals that the Earth's early atmosphere periodically flipped from a hydrocarbon-free state into a hydrocarbon-rich state similar to that of Saturn's moon, Titan.

This switch between "organic haze" and a "haze-free" environment was the result of intense microbial activity and would have had a profound effect on the climate of the Earth system.

Similar to the way scientists believe our climate behaves today, the team say their findings provide us with an insight into the Earth's surface environment prior to oxygenation of the planet.

Study lead Dr Aubrey Zerkle, based in the School of Civil Engineering and Geosciences at Newcastle University, explains: "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.

"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."

Dr Zerkle, working along with Dr James Farquhar at the University of Maryland, USA, and Dr Simon Poulton at Newcastle University, UK, analysed the geochemistry of marine sediments deposited between 2.65 and 2.5 billion years ago in what is now South Africa.

They found evidence of local production of oxygen by microbes in the oceans, but carbon and sulphur isotopes indicate that little of that oxygen entered the atmosphere.

Instead, the authors suggest that the atmosphere transitioned repeatedly between two states: one with a thin, hydrocarbon haze and the other haze-free. These geochemical records were supported by models of the ancient atmosphere performed by colleagues at the NASA Astrobiology Institute, led by Dr Mark Claire (currently at the University of East Anglia, UK) and Dr Shawn Domagal-Goldman, which demonstrated how the transitions could be caused by changes in the rate of methane production by microbes.
The conditions which enabled the bi-stable organic haze to form permanently ended when the atmosphere became oxygenated some 100 million years after the sediments were laid down.

"What is most surprising about this study is that our data seems to indicate the atmospheric events were discrete in nature, flip-flopping between one stable state into another," explains co-author Dr Farquhar.

"This type of response is not all that different from the way scientists think climate operates today, and reminds us how delicate the balance between states can be."

Professor Mark Thiemens, Dean of Physical Sciences at the University of California San Diego, adds: "Another important facet of the work is that it provides insight into the formation of atmospheric aerosols, particularly organic ones.

"Besides the obvious importance for the evolution of the atmosphere, the role of aerosol formation is one of the most poorly understood components in the present day climate models. This provides a new look into this process that is quite new and valuable."

Dr. Aubrey Zerkle | EurekAlert!
Further information:
http://www.newcastle.ac.uk

More articles from Earth Sciences:

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

nachricht Modeling magma to find copper
13.01.2017 | Université de Genève

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>