The Commercial-News, Danville, IL

Community News Network

January 1, 2013

Fossils may date from 3.5 billion years ago

(Continued)

"It's not just finding this stuff that's interesting," says Alan Decho, a geobiologist at the University of South Carolina's Arnold School of Public Health. "It's showing that the life had some organization to it." Ridges that crisscross the rocks like strands in a spider web hint that primitive bacteria linked up in sprawling networks. Like their modern counterparts, they may have lived in the equivalent of microbial cities that hosted thousands of kinds of bacteria, each specialized for a different task and communicating with the others via chemical signals.

Many of the textures seen in the Australian rocks had already shown up in 2.9-billion-year-old rocks from South Africa, reported on by Noffke and colleagues in 2007.

Still, old Australian rocks have proved deceptive before. As early as 1980, rippling layers within the Strelley Pool were thought to be the handiwork of bacteria. But such stromatolites, which are different from the structures that Noffke studies, can also be the work of natural, non-living processes. For instance, water flowing along a seafloor can create similar structures under the right conditions. So can spraying jets of liquid loaded with particles onto a surface, as scientists at Oxford University demonstrated in laboratory experiments.

That's why Noffke and her colleagues corroborated their story by measuring the carbon that makes up the textured rocks. About 99 percent of carbon in non-living stuff is carbon-12, a lighter version of the element than the carbon-13 that accounts for most of the remaining 1 percent. Microbes that use photosynthesis to make their food contain even more carbon-12 and less carbon-13. That bias, a signature of "organic" carbon that comes from a living being, showed up in the Australian rock.

"It's always nice to have a number of different lines of evidence, and you definitely want to see organic carbon," says geomicrobiologist John Stolz of Duquesne University in Pittsburgh.

Text Only
Community News Network
E-edition
AP Video
The Carbon Trap: US Exports Global Warming UN Security Council Calls for Gaza Cease-fire Traditional African Dishes Teach Healthy Eating 13 Struck by Lightning on Calif. Beach Baseball Hall of Famers Inducted Israel, Hamas Trade Fire Despite Truce in Gaza Italy's Nibali Set to Win First Tour De France Raw: Shipwrecked Concordia Completes Last Voyage Raw: Sea Turtle Hatchlings Emerge From Nest Raw: Massive Dust Storm Covers Phoenix 12-hour Cease-fire in Gaza Fighting Begins Raw: Bolivian Dancers Attempt to Break Record Raw: Israel, Palestine Supporters Rally in US Raw: Air Algerie Flight 5017 Wreckage Virginia Governor Tours Tornado Aftermath Judge Faces Heat Over Offer to Help Migrant Kids Kangaroo Goes Missing in Oklahoma More M17 Bodies Return, Sanctions on Russia Grow Raw: Deadly Tornado Hits Virginia Campground Ohio State Marching Band Chief Fired After Probe
NDN Video
Big Weekend For Atlanta Braves In Cooperstown - @TheBuzzeronFox Chapter Two: Becoming a first-time director What's Got Jack Black Freaking Out at Comic-Con? Doctors Remove 232 Teeth From Teen's Mouth Bradley Cooper Explains His Voice in 'Guardians of the Galaxy' Deja vu: Another NYPD officer choke-holding a suspect 'Fifty Shades of Grey': Watch the Super Sexy First Trailer Now! Reports: Ravens RB Ray Rice Suspended For 1st 2 Games Of The Season Air Algerie plane with 119 on board missing over Mali Diamond Stone, Malik Newman, Josh Jackson and others showcase talent Free Arturo - The World's Saddest Polar Bear A Look Back at Batman On Film Through The Years LeBron James -- Dropped $2k On Cupcake Apology ... Proceeds To Benefit Charity Snoop Dogg Says He Smoked Weed at the White House Raw: Fight Breaks Out in Ukraine Parliament Chris Pratt Interrupts Interview To French Braid Intern's Hair Shirtless Super Mario Balotelli Dances While Ironing - @TheBuzzeronFOX Whoa! Watch "Housewives" Star Do the Unthinkable LeBron apologizes to neighbors with cupcakes Justin Bieber In Calvin Klein Underwear Shoot
Must Read