Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Earliest life or rare dirt?

07.03.2002


Life forms: Schopf thinks these marks are fossils of ancient bacteria.
© Nature


Dishing the dirt: Brasier’s team reckons geological processes made the squiggles.
© Nature


Gloves are coming off in ancient bacteria bust-up.

A claim to have found evidence of the oldest living things on Earth is being fiercely contested. The argument looks set to run and run, and no one may win, but it may lead to a better understanding of the origins of life on our planet.

The debate is academic, but its implications are not. The ’fossil bacteria’ in question are around 3.5 billion years old. That’s roughly one billion years older than the only confirmed fossil bacteria.



This would mean that complex biochemistry - including photosynthesis - originated around one billion years after the Earth formed. Photosynthesis released oxygen into the atmosphere, which has supported the majority of life ever since.

Dark microscopic squiggles in rocks called ’Apex chert’ from Western Australia, are the fossils of various species of cyanobacteria, according to William Schopf of the University of California, Los Angeles1.

A team led by Martin Brasier at the University of Oxford, UK, believes that Schopf’s ’fossils’, although unusual, are simply tiny clumps of impurities in the rock2.

Fellow researchers are loath to be named for fear of "exacerbating what looks like becoming an acrimonious debate", according to one. They are nonetheless following the details closely. "This is a fascinating debate," says another.

Most agree that the age of the Apex chert rocks may preclude either side ever being proved right.

Technical point

Schopf’s team studied the structure and chemical composition of the squiggles with a technique called laser-Raman imagery. The group argues that the marks are made up of carbon molecules, which are the decay products of living bacterial cells. "They are tiny little fossils," says Schopf.

Brasier’s team repeated some of Schopf’s analyses recently and disagrees. "Schopf’s hypothesis is deeply flawed," Brasier says.

Brasier’s team agrees that the marks’ chemical composition appears biological in origin. But the group thinks that they actually arose through unusual geological processes around ancient hydrothermal vents, where hot volcanic gases rise to the surface.

What’s more, the group says, the squiggles look nothing like other ancient microbes. "The shapes are far too complicated to be bacteria," says Brasier, who feels Schopf should drop his claim.

Brasier’s group asserts that biological-seeming molecules can result from reactions between the carbon dioxide and monoxide released by hot, metal-rich hydrothermal vents. These molecules could then have been sculpted into bacteria-esque filaments as the hot rocks they were born in cooled.

If this was the case, argues Schopf, such material would be found everywhere. So far it hasn’t been. "The facts are going to win and I’ve got the data," he says.

Win-win?

The one thing both parties agree on is that only time will tell. Schopf is continuing to analyse his putative fossils. A nanoscale examination of their ’cell membranes’ will, he claims, prove beyond doubt that the Apex chert does contain the oldest known remains of life on Earth.

Brasier and his team are now investigating the kind of chemical reactions that they believe produced the squiggles. The researchers suspect the reactions could themselves have created complex molecules such as amino acids and be the source of life on Earth. "Schopf may have stumbled on a site that may explain how life got started," says Brasier.

References

  1. Schopf, J. W., Kudryavtsev, A. B., Agresti, D. G., Wdowiak, T. J. & Czaja, A. D. Laser-Raman imagery of Earth’s earliest fossils. Nature, 416, 73 - 76, (2002).
  2. Brasier, D. M. et al. Questioning the evidence for Earth’s oldest fossils. Nature, 416, 76 - 81, (2002).

TOM CLARKE | © Nature News Service

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>