Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study shows our ancestors survived ’Snowball Earth’

07.06.2006


It has been 2.3 billion years since Earth’s atmosphere became infused with enough oxygen to support life as we know it. About the same time, the planet became encased in ice that some scientists speculate was more than a half-mile deep. That raises questions about whether complex life could have existed before "Snowball Earth" and survived, or if it first evolved when the snowball began to melt.



New research shows organisms called eukaryotes -- organisms of one or more complex cells that engage in sexual reproduction and are ancestors of the animal and plant species present today -- existed 50 million to 100 million years before that ice age and somehow did survive. The work also shows that the cyanobacteria, or blue-green bacteria, that put the oxygen in the atmosphere in the first place, apparently were pumping out oxygen for millions of years before that, and also survived Earth’s glaciation.

The findings call into question the direst models of just how deep the deep freeze was, said University of Washington astrobiologist Roger Buick, a professor of Earth and space sciences. While the ice likely was widespread, it probably was not consistently as thick as a half-mile, he said.


"That kind of ice coverage chokes off photosynthesis, so there’s no food for anything, particularly eukaryotes. They just couldn’t survive," he said. "But this research shows they did survive."

Buick and colleagues studied droplets of oil encased in rock crystals dating from 2.4 billion years ago, recovered from the Elliot Lake area near Sault Ste. Marie, Ontario, Canada. The oil, essentially chemicals left from the breakdown of organic matter, contained biomarkers, or molecular fossils, that can be structurally identified as having come from specific types of life.

"It’s the same thing as looking at dinosaur fossils, except these fossils are at the molecular scale. You are looking at the molecular skeletons of carbon molecules, such as cholesterol, held within oil droplets," he said.

This is not the first time biomarkers indicating that eukaryotes and cyanobacteria were alive before "Snowball Earth" have been found in ancient rocks. A paper reaching the same conclusion was hailed as one of the top science breakthroughs of 1999. Buick did some of the research for that paper and was a co-author. But almost from its publication, detractors have said what was seen were not really ancient biomarkers but rather some kind of contamination that got into the samples being studied, possibly from oil flowing through shale rocks at a much later time or modern fossil fuel pollution.

"The contamination idea has always been nattered about in corridors or talked about in meetings, but never put down in print," Buick said. "What this new paper does is confirm these as being very, very old biomarkers."

The lead author of the paper, published in the June edition of Geology, is Adriana Dutkiewicz of the University of Sydney in Australia, for whom Buick served as a postdoctoral mentor. Other authors are Herbert Volk and Simon George of the Commonwealth Scientific and Industrial Research Organization in Australia and John Ridley of Colorado State University.

The researchers examined rock samples obtained from an outcrop near Elliot Lake, which then were fragmented into pieces less than one-tenth of an inch in diameter. The particles were cleaned thoroughly and checked for contamination throughout the process. The crystal fragments contained numerous minuscule pockets of fluid mostly consisting of water but also containing small amounts of oil, usually in a thin film around a bubble of water vapor. The oil resulted from decaying organic matter, probably of marine origin.

"A drop of oil is a treasure trove. It is highly concentrated molecular fossils," Buick said.

The biomarkers contained in the oil indicate that both eukaryotes and cyanobacteria first appeared before the planetary glaciation, rather than evolving at the same time or later, he said. The samples also suggest that oxygen was being produced long before the atmosphere became oxygenated, probably oxidizing metals such as iron in the Earth’s crust and ocean before the atmosphere began filling with oxygen.

Vince Stricherz | EurekAlert!
Further information:
http://www.washington.edu

More articles from Earth Sciences:

nachricht Modeling magma to find copper
13.01.2017 | Université de Genève

nachricht What makes erionite carcinogenic?
13.01.2017 | Friedrich-Schiller-Universität Jena

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

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

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>