Research led by a NASA astrobiologist in 2010 that suggested the existence of bacteria could grow using arsenic instead of phosphorus has been challenged by two new studies.
It was a provocative finding: strange bacteria in a California lake that thrived on something completely unexpected — arsenic. What it suggested is that life, a very different kind of life, could possibly exist on some other planet.
The research, published by a leading scientific journal in 2010, led to overheated speculation about how life might exist elsewhere — and quickly some dissent about the original finding.
On Sunday, that same journal, Science, released two papers that rip apart the original research. They "clearly show" that the bacteria can't use arsenic as the researchers claimed, said an accompanying statement from the journal.
The saga began when scientists led by Felisa Wolfe-Simon of NASA's Astrobiology Institute published a paper that said the bacteria, found at Mono Lake in eastern California, could grow by substituting arsenic for phosphorus. The researchers had looked at Mono Lake because of its high arsenic levels, and they reported their conclusions from lab experiments.
Their paper raised eyebrows because phosphorus was considered essential to life, while arsenic, while chemically similar, is a poison.
If the bacteria can break the rules like this, some argued, who knows what kinds of life may be possible beyond Earth?
But not everybody bought the conclusions of the paper. Last year, Science published a bunch of challenges from other scientists, and the paper has long been an object of skepticism.