New findings by University of Washington scientists could change the timeline of how life evolved on Earth, and maybe on other planets, too.
The research has to do with nitrogen, a crucial ingredient of life. Scientists had believed usable nitrogen was in very short supply on the young planet, without the enzymes needed to break it down.
UW Earth and Space Sciences professor Roger Buick says life on Earth earlier than about two billion years ago was thought to be little more than a smudge.
“There would have just been a small biosphere of small organisms that weren’t very abundant – a microbial scum in the oceans, maybe,” Buick said.
But then he and grad student Eva Stueken analyzed a batch of very ancient rocks, mostly shale form South Africa and Australia. In those rocks that are three billion years old, they discovered a relative bonanza of nitrogen. This showed that early single-celled organisms had figured out how to make use of the nitrogen in the atmosphere.
That means the Earth may have had much richer life a good billion years earlier than thought.
“Well, we could have had a large biosphere with lots of organisms living in lots of different habitats, because there wasn’t this restriction,” Buick said.
Buick, who also studies astrobiology, said the findings have implications for other planets. Mars, for example, could probably have supported life for just one or one-and-a-half billion years. The new research suggests any life on Mars could have progressed fairly far during that short time.
The results are published in the journal "Nature."
