. 24/7 Space News .
Astrobiologists Find Evidence Of Early Ground Hoggers

graphic based upon surface rendering by David Seal's planet art collection at JPL
Moffett Field - Nov. 29, 2000
Scientists with NASA's Astrobiology Institute (NAI) have discovered fossilized remnants of microbial mats that developed on land between 2.6 billion and 2.7 billion years ago in the Eastern Transvaal district of South Africa.

This significant discovery presents the strongest evidence to date that life on land occurred at a much earlier stage in Earth's history than was previously believed by most scientists. It also suggests that an ozone shield and an oxygen-rich atmosphere existed on Earth 2.6 billion years ago, both necessary conditions for life on land to emerge. The results are reported in the Nov. 30 issue of Nature magazine.

"This important investigation undertaken by an NAI team feeds into NASA's strategy of using Earth analogs, particularly analogs present on early Earth, as models for testing the hypothesis that life exists, or has existed, on Mars or elsewhere in the universe," said Dr. Baruch Blumberg (Nobel '76), director of the NAI research consortium. "A major goal of the NAI is to undertake the basic science that is necessary for the performance of NASA and space science missions."

The finding also has other important implications for NASA. "The suggestion that an ozone shield existed as early as 2.6 billion years ago boosts our chances in the search for life on planets orbiting other stars," said Dr. Michael Meyer, astrobiology discipline scientist at NASA Headquarters, Washington, D.C. "Ozone would be easily detectable by the Terrestrial Planet Finder, a planned interferometer mission in NASA's 'Origins' program."

The microbial mats discovered by researchers are composed primarily of cyanobacteria, the principal organisms that generate oxygen from water and atmospheric carbon dioxide using sunlight.

"This discovery is similar to what scientists went through with marine organisms," said Dr. Hiroshi Ohmoto, co-author of the Nature report, a member of the NAI, director of the Astrobiology Research Center and a faculty member in the Department of Geosciences at The Pennsylvania State University. "Once scientists thought no living organisms existed in the Earth's oceans before 500 million years ago. Then they studied the carbonaceous matter in ancient sedimentary rocks deposited in the oceans and found that organisms lived in the oceans at least 3.8 billion years ago," he said.

A variety of geochemical and paleontological data suggests that microorganisms flourished in Earth's oceans at least 3.8 billion years ago, but researchers have been unable to agree on when microorganisms first colonized the land. The oldest undisputed remains of terrestrial organisms are currently 1.2 billion-year-old microfossils discovered in 1994 in Arizona by Dr. Paul Knauth, a member of the NAI-Arizona State University astrobiology team. However, many scientists think the Earth's land surface was sterile until about 500 million years ago, when vesicular plants first appeared.

Ohmoto noted that the organic matter found in South Africa occurred primarily as parallel seams in the ancient 2.6 billion-year-old soil bed. This suggests that the organic seams are remnants of biomats that developed on the soil surface and were trapped while the soil formed. The team discovered the "right" ratios of chemical elements essential for life (carbon, hydrogen, nitrogen and phosphorous) in the carbonaceous matter of the Eastern Transvaal. This provides strong evidence that the carbonaceous matter is of biological rather than abiotic origin, according to Ohmoto.

The Pennsylvania State University is a member of, and receives research funding for this and other efforts through, NASA's Astrobiology Institute, a research consortium encompassing academic and non-profit organizations plus NASA field centers. The NAI's central administrative office is located at NASA's Ames Research Center in California's Silicon Valley. In addition to full members, the NAI has international affiliate and associate members. Astrobiology is the study of the origin, evolution, dissemination and future of life in the universe. NASA's exobiology program also funded the subject research.

Yumiko Watanabe, senior author of the Nature article, is a doctoral student of Ohmoto's at The Pennsylvania State University. Dr. Jacques Martini, another co-author, is a member of the Geological Survey of South Africa in Pretoria, and an associate member of The Pennsylvania State University Astrobiology Research Center.

Related Links
Astrobiology Com
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express

Did Life Drip Down From Earth's Ancient Atmosphere
 Washington - Oct. 17, 2000
An international team of researchers has proposed a new theory that aerosol particles in the ancient atmosphere may have played a role in generating the chemical building blocks for life on Earth. Indeed, they say, the aerosols may have had many characteristics of a primitive form of "cell".



Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only














The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.