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Life on Earth began much earlier: new research
May 29, 2008
Stromatolites at Shark Bay, Western Australia
The researchers receive a Eureka Award in 2005 (from left to right: Professor Neilan, Dr Burns and Professor Walter).
New studies of the world's most primitive living things - colonies of bacteria found on the Western Australia coast - suggest that life on Earth may have begun much earlier than the accepted date of about 3.5 billion years ago.
The colonies build rock-like structures, known as stromatolites, in tidal pools at Shark Bay: research has revealed that they are comparable with ancient stromatolite fossils found in the nearby Pilbara region, which are the oldest convincing evidence of life.
Sophisticated investigations by a team at the UNSW Australian Centre for Astrobiology (ACA) have now revealed that the colonies are very biologically diverse - involving many more than just a few species as previously thought - and that the same was probably true of the 3.5 billion-year-old Pilbara stromatolites.
"Powerful new chemistry and genomic tools have revealed that the Shark Bay stromatolites have remarkable biodiversity, with evidence so far of more than 100 species of bacteria," says ACA Deputy Director Professor Brett Neilan.
"In effect, this suggests that by 3.5 billion years ago Earth was already teeming with diverse microbial life. If this is so, evolution must have already been going on for a long time. We can't be sure, but certainly many tens of millions of years earlier. These findings could reset the start of the clock of life."
ACA Director Professor Malcolm Walter says the findings also add a fresh perspective on the long-standing controversy about whether oxygen-releasing cyanobacteria were already present at that time.
"The release of oxygen to the oceans and atmosphere changed the Earth forever and set the scene for all subsequent evolution," Professor Walter notes. "We would not be here were it not for this event, and there is no better place than Australia to study such an important evolutionary episode."
The findings take on added relevance for the ongoing search for signs of life on Mars, with the successful landing on the planet earlier this week of the Phoenix spacecraft.
Professor Walter is also a member of an international group planning the first two-way mission to Mars, which aims to return samples to Earth from carefully selected sites on Mars most likely to have evidence of life. That mission cannot occur before 2018.
Professor Walter says that this will be one of the greatest exploration missions in human history, and Australian scientists are ready to make a substantial contribution. Lessons learned from Shark Bay and the Pilbara will play a vital role.
The centre is being relaunched to mark its move to the University of New South Wales, in Sydney. Guest speaker at the event is the Australian astronaut Andy Thomas.
The ACA is the focus for a broad research network that includes a wide range of researchers at UNSW and elsewhere studying the origins of life of Earth and evidence for possible life elsewhere in the Universe.
They include eminent astronomers Professor John Webb and Professor Chris Tinney in the UNSW School of Physics, who are looking further afield at planetary systems beyond our own. They are part of a growing movement probing the processes of planet formation and, ultimately, evaluating the possibility of life elsewhere in the Universe.
Additional background:
Astrobiology is a relatively new field of study, developing at the crossroads of astronomy, biology, geology, palaeontology, physics and other disciplines.
Recent discoveries in this field are rapidly changing our view of the potential for life elsewhere in the Universe, as is the international Search for Extraterrestrial Intelligence (SETI) project.
Advances in remote-detection technologies have enabled astronomers to identify hundreds of planetary systems similar to our own, and the search for Earth-like planets continues at a breathtaking pace.
Of perhaps even greater significance is a growing appreciation that life can exist under conditions previously thought impossible. These include microbes flourishing under extremes of pressure on the ocean floor, at temperatures above boiling and below freezing, and in the intense radiation conditions found in outer space.
The ACA has developed, in association with NASA, a "virtual field trip" that allows students to join scientists in the field in the Pilbara and Shark Bay areas, and to understand the relevance of Australian science in understanding our origins and in searching for life elsewhere in the universe. One developers of that project, science communication specialist Carol Oliver, says: "Young people are fascinated by the challenges of planetary exploration. Astrobiology is a very effective way to encourage students to take up studies in science and engineering because it opens them to the nature of science - to understand that science is about pushing back the frontiers of our knowledge about the natural world."
All ACA doctoral students have the opportunity to spend time at NASA in some capacity during their PhD studies and the first three ACA graduates are all now working at NASA. The ACA is one of only two international associate members of the NASA Astrobiology Institute. The other is in Spain.
Professor Walter, Professor Neilan and Dr Burns were awarded a prestigious Eureka Award in 2005 to acknowledge the success of their interdisciplinary research. The Federal Government recently awarded Professor Neilan a Federation Fellowship.
Media coverage:
Australian Life Scientist: http://www.biotechnews.com.au/index.php/id;36530141;fp;2;fpid;1
ABC Science Online: http://www.abc.net.au/science/articles/2008/05/29/2258987.htm?site=science&topic=latest
Sydney Morning Herald: http://www.smh.com.au/news/science/earlier-start-to-life-on-earth/2008/05/29/1211654221563.html
Contacts
Media liaison: Bob Beale - 0411 705 435
ACA liaison: Carol Oliver - 0417 477 612
UNSW Australian Centre for Astrobiology (ACA): http://aca.unsw.edu.au/
