Bacteria Fossils

Alive. . . after 250 million years

The bacterium lived millions of years before the dinosaurs

October 18, 2000 - BBC

Scientists in the United States have revived a 250-million-year-old bacteria that is believed to be the oldest living creature ever discovered.

The bacterium that lived millions of years before the dinosaurs was in a state of suspended animation in an ancient salt crystal in an underground cavern near Carlsbad, New Mexico.

``From a biological standpoint this is extremely significant because quite literally this organism is the next best thing to having been there,'' Russell Vreeland, a microbiologist at West Chester University in Pennsylvania, said in a telephone interview.

Hundred-million-year-old fossils and rocks give geologists clues about the Earth's past but until now researchers have not had anything to reveal the secrets of life that long ago.

``Now we have at least one organism that goes back that far that we can ask biological questions of...something that we couldn't do before,'' Vreeland added.

Protective Shell Saved It From The Elements

The crystal that contained the bugs

The fact that Vreeland and his colleagues were able to bring the sleeping bacterium, called Bacillus permians, back to life after so long opens up the possibility that bacterial spores could live indefinitely.

``If something can survive 250 million years, what's the difference in another 250 or longer,'' Vreeland said.

The bacterium was trapped in a tiny brine pocket in the salt from ancient rock formations.

``It was completely protected,'' said Vreeland, whose research is published in the science journal Nature.

``It was able to shut itself down into a protective spore and once it was encased within this particular type of rock it found itself in the most stable environment that you could imagine.''

The scientists carefully drilled into the crystal under the most sterile conditions, extracted fluid from it, placed the fluid in sealed test tubes and incubated it until it grew.

The extraordinary age of the bacterium also begs the question of whether organisms can survive long enough to travel between planets.

``If an organism were encased in a crystal and blown off a planet somewhere, or blown off of this one due to a meteor collision, it has a reasonable probability of surviving long enough to travel not just from planet to planet but solar system to solar system,'' Vreeland said.

The scientists are comparing the bacterium to its modern relatives and are now looking for even older organisms.

``We are already starting to look at some 500-million-year-old and 800-million-year-old samples and we're working on some that are even older than that,'' Vreeland added.

Study provides evidence of early oxygen-producing organisms

Cyanobacteria - they changed the face of the Earth

August 5, 1999 - AP

The earliest direct evidence of organisms releasing oxygen into Earth's atmosphere has been found in the ancient remains of bacterial slime from Australia, researchers reported Wednesday.

The 2 1/2 billion-year-old molecular fossils show that early forms of life began paving the evolutionary path for oxygen-breathing animals at least 700 million years earlier than previously known.

Rod-shaped cyanobacteria found in Australia

"Life wouldn't be what it is today if we didn't have oxygen in the atmosphere and in the ocean," said Roger Summons, the chief research scientist for the Australian Geological Survey Organization and the lead author of the study in Wednesday's journal Nature.

The research may also provide a tool in the search for life on Mars.

Scientists had long suspected that organisms called cyanobacteria first started converting sunlight and carbon dioxide into food energy and oxygen billions of years ago. But no evidence had been previously found in fossils.

Summons and his colleagues tested samples from a drill core in Western Australia's Hammersley Basin, one of the most geologically stable areas on Earth, and later, samples from Mexico, Germany and Israel.

They discovered a durable molecular signature - "fingerprints" - unique to certain cyanobacteria that lived on the shores of the ancient oceans, long before plants, animals and other complex life emerged.

"This is the first good evidence of early oxygenic photosynthesis," said Jere Lipps, professor of biology at the University of California, Berkeley. "That's important because we couldn't be certain based on microfossils or other geologic evidence."

The technique of identifying the molecular signature of ancient organisms also could be used in the hunt for life elsewhere in the universe.

David McKay, a NASA researcher who led a 1996 team that announced a meteorite from Mars showed evidence of ancient life, agreed.

"This is really potentially useful," he said Wednesday. "We think that this is the first of a number of molecular biomarkers that may be documented in the future and that can be applied directly to returned Mars samples."

The markers discovered by Summons' team survived 2 1/2 billion years on Earth. Mars, a quieter place geologically, could preserve the record even longer, McKay said.

Forms of cyanobacteria exist today, often referred to as blue-green algae because they resemble the slimy substance. They can be found in places like the hot springs of Yellowstone National Park.

The microbes may have been pumping oxygen into the atmosphere for as long as 3 1/2 billion years - 1 billion years after the Earth formed.

"The further you go back, there are fewer and fewer well-preserved samples," said Linda Jahnke, a study co-author and bacteriologist at NASA's Ames Research Center in Moffett Field. "It's a fact of the reworking of the surface of the Earth. Things are being buried all the time."

3.7 billion-year-old plankton found in Greenland

January 29, 1999 - AP

Danish researchers have found evidence of what they believe to be the world's oldest fossils -- plankton dating back 3.7 billion years in Greenland, according to Journal of Science

The oldest fossils found to date were bacteria believed to be 3.5 billion years old, according to researchers who said that the bacteria were more complex than the Greenland find.

Scientists have long believed that the bacteria evolved from more primitive ancestors, although Earth's geological changes have wiped out most fossil traces. In the absence of any real fossil record, geologist Minik Rosing of the Geological Museum of Copenhagen tried to find the fossil record in the chemical detritus, or debris left by the organisms when they disappeared.

Looking for microscopic traces of carbon left by primitive plankton, Rosing and his team went to western Greenland to search for sedimentary rocks on the bottom of a 3.7 billion-year-old ocean. "These data and the mode of occurrence indicate that the reduced carbon represents biogenic detritus which was perhaps derived from planktonic organisms," Rosing wrote in Science.