This site is not maintained. Click here for the new website of Richard Dawkins.

Fossil microbes give sulphur insight on ancient Earth

Tiny structures found in 3.4bn-year-old sandstones in Western Australia represent some of the oldest, best preserved evidence of life on Earth.

Scientists say their analysis of the microfossils clearly shows the organisms were processing sulphur for energy and growth - not oxygen.

They report their discovery in the journal Nature Geoscience.

The team says the microbe remains offer a fascinating insight into conditions on the ancient Earth.

"At last we have good solid evidence for life over 3.4 billion years ago. It confirms there were bacteria at this time, living without oxygen," said co-researcher Professor Martin Brasier at Oxford University, UK.

"Such bacteria are still common today. Sulphur bacteria are found in smelly ditches, soil, hot springs, hydrothermal vents - anywhere where there's little free oxygen and they can live off organic matter," he explained.

The fossils were first identified in 2007 at Strelley Pool, a remote location of the Pilbara, a dry region about 60km west of Marble Bar.

alt text
The fossils were found in sandstones found at the base of these prominent ridges

Their host sandstones were laid down in what would have been a shallow-water beach or estuary.

They measure just a few millionths of a metre (microns) across and have been subjected in recent years to a series of advanced analytical techniques to probe their origin.

The scientists say they are now confident that the spheroidal and ellipsoidal forms buried in the rock are the remains of bacterial cells, along with the protective tubes that once housed them.

Form and behaviour are good indicators. The shape and clustering are reminiscent of bacterial cells. But more than that, the fossils are associated with tiny crystals of "fool's gold" - the pyrite mineral composed of iron and sulphur.

The types of atoms, or isotopes, present in these crystals point to the pyrite being formed as a by-product of cellular metabolism based on compounds of sulphur.

"Life likes lighter isotopes, so if you have a light signature in these minerals then it looks biological," said lead author Dr David Wacey from the University of Western Australia.

Read on

TAGGED: BIOLOGY, EVOLUTION, SCIENCE


RELATED CONTENT

Bonobo makes stone tools like early...

Hannah Krakauer - New Scientist Comments

Kanzi the bonobo is able to create and use stone tools

Scientists Discover Previously Unknown...

- - URMC Comments

Newer Imaging Technique Brings ‘Glymphatic System’ to Light

Grey parrots use reasoning where...

- - The Royal Society Comments

Research suggesting that grey parrots can reason about cause and effect from audio cues alone- a skill that monkeys and dogs lack- is presented in Proceedings of the Royal Society B today.

Why do organisms build tissues they...

- - Science Blog Comments

Why, after millions of years of evolution, do organisms build structures that seemingly serve no purpose?

New flat-faced human species possibly...

Charles Choi - CBS News Comments

Four decades ago, in 1972, the Koobi Fora Research Project discovered the enigmatic fossilized skull known as KNM-ER 1470 which ignited a now long-standing debate about how many different species of early Homos existed.

A New Species Discovered ... On Flickr

Adam Cole - NPR Comments

One day in May of 2011, Shaun Winterton was looking at pictures of bugs on the Internet when something unusual caught his eye. It was a close shot of a green lacewing — an insect he knew well — but on its wing was an unfamiliar network of black lines and a few flecks of blue.

MORE

MORE BY JONATHAN AMOS

Nasa's Curiosity rover zaps Mars rock

Jonathan Amos - BBC News Comments

Pew pew pew pew

LHC reports discovery of its first new...

Jonathan Amos - BBC News Science &... 24 Comments

The Large Hadron Collider (LHC) on the Franco-Swiss border has made its first clear observation of a new particle since opening in 2009.

African fossils put new spin on human...

Jonathan Amos - BBC News -Science &... 23 Comments

Features seen in the brain, feet, hands and pelvis of A. sediba all suggest this species was on the direct evolutionary line to us - Homo sapiens.

Cosmic distance record 'broken'

Jonathan Amos - BBC News, Science &... 40 Comments

A cataclysmic explosion of a huge star near the edge of the observable Universe may be the most distant single object yet spied by a telescope.

Fossils may be 'earliest animals'

Jonathan Amos - BBC 8 Comments

Planck telescope reveals ancient cosmic...

Jonathan Amos - BBC 20 Comments

MORE

Comments

Comment RSS Feed

Please sign in or register to comment