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 Mountain glaciers shrinking across the West
23.10.2017 | University of Washington

nachricht Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Symposium on Driving Simulation

23.10.2017 | Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

 
Latest News

Introduction of a novel system for in vitro analyses of zebrafish oligodendrocyte progenitor cells

23.10.2017 | Life Sciences

Did you know how many parts of your car require infrared heat?

23.10.2017 | Automotive Engineering

3rd Symposium on Driving Simulation

23.10.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>