Evidence of one of the earliest forms of life has been discovered in a remote region in western Australia.
A team of researchers from the University of Western Australia looking in the country’s Pilbara district, home to the world’s oldest rock formations, found bacterial ecosystems that had never been seen in this area before. The microbially induced sedimentary structures, or MISS, are believed to be 3.5 billion years old. The findings, published in the journal Astrobiology, may inform the search for life forms on other planets.
These bacteria are “possibly the oldest signs of life on Earth," said UWA's David Wacey, whose team describes finding various MISS preserved in the Dresser Formation and explains how they used advanced chemical analyses to determine how old the microbial samples are.
"This work extends the geological record of MISS by almost 300 million years," Noffke, Hazen, from Old Dominion University, said in a statement. "Complex mat-forming microbial communities likely existed almost 3.5 billion years ago."
While the cells can no longer be seen under the microscope, there are marks left behind created by large clusters of microbes. "We don't see the microbe themselves, but we see large-scale structures that the microbes constructed before they died," Wacey told The Telegraph.
Other ancient life forms have been observed in the region before. Stromatolites, mound-like deposits created by ancient photosynthetic bacteria, and microfossils of bacteria were previously found there, indicating the area holds clues to the early evolution of life.
In the latest findings, Wacey describes seeing “filaments tangled in sand grains” as well as a “mass of carbon-rich material.” The findings may shed light on how to discover life in space.
"These microbial mats could be seen by a Mars rover,” Wacey said. “It also helps with our understanding of when life first evolved and what sort of environment it evolved in and putting firm dates on when some pretty important things happened. Ultimately, we are looking for when that soup of chemicals became something that could be called life."