"People have been looking for signs of early bacteria for the last 50 years," said Dr. Karlis Muehlenbachs, from the U of A's Faculty of Science and an author on the paper just published in the journal Science. "A variety have claimed they've seen it and subsequently been challenged as being flawed. We are suggesting that we have clear evidence of life prospering in an environment where no one else has bothered to look."
The research team, also made up of Drs. Harald Furnes from the University of Bergen in Norway, Neil Banerjee from the U of A, Hubert Staudigel from the University of California and Maarten de Wit from the University of Cape Town, studied samples of pillow lava taken from the Mesoarchean Barberton Greenstone Belt in South Africa. They found mineralized tubes that were formed in the pillow lava, suggesting microbes colonized basaltic glass of the early oceanic crust, much in the same way as they do modern volcanic glass.
This evidence of life in the basaltic glass on the seafloor comes in the form of textures produced by microbes as they dissolve the glass, said Banerjee. "These textures include channels or tubes produced by the microbe as it tunnels through the glass, possibly using the glass as a source of nutrients," he said. "We have also found traces of carbon, nitrogen, phosphorous and potassium-all essential to life-as well as DNA associated with the microbial alternation textures in the recent basaltic glass samples."
The team then compared its $3.5 billion-year-old samples to the modern pillow lava on the seafloor using several sophisticated tests and was able to find much evidence of life. To date the microbial activity, the team compare
Contact: Phoebe Dey
University of Alberta