‘Arsenic Life' Microbe Study Retracted after 15 Years of Controversy
The claim was controversial because it flew in the face of well-established biochemistry. Of the many elements thought crucial for life, one of the most important is phosphorus, which serves as a building block for DNA and other biomolecules. But in samples from California's Mono Lake, a research team had found evidence of a bacterium swapping out phosphorus for arsenic. If true, the result would've rewritten textbooks and led to radical revisions in our understanding of where and how life might crop up elsewhere in the cosmos. The trouble was: many experts weren't convinced.
Now, some 15 years later, the venerable scientific journal has retracted this 'arsenic life' study, once the star of a NASA news conference because of its epochal astrobiological implications. First elevating an early-career U.S. Geological Survey researcher, Felisa Wolfe-Simon, to acclaim, then to controversy, the study convulsed the scientific community for two years, raising questions over how science is both conducted and publicized.
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' Science has decided that this Research Article meets the criteria for retraction by today's standards,' said the journal's editor-in-chief Holden Thorp in the July 24 retraction notice. While Science 's earlier standards only allowed for the retraction of a study because of fraud or misconduct, he explained, the journal now allows for removal if a paper's experiments don't support its key conclusions. He pointed to two 2012 studies, also published by Science, that suggested the Mono Lake microbe, dubbed GFAJ-1, merely sequestered arsenic extraordinarily well internally and didn't rely on it for its metabolism or reproduction. 'Given the evidence that the results were based on contamination, Science believes that the key conclusion of the paper is based on flawed data,' states a follow-up blog post co-authored by Thorp and Valda Vinson, executive editor for the Science journals. Ten Science studies have been retracted for unintended error since 2019, according to a spokesperson for the journal.
The study's authors, including Wolfe-Simon, protested the retraction in a letter to Science. 'Claims should be made, tested, challenged, and ultimately judged on the scientific merits by the scientific community itself,' they wrote.
One of the study's authors, geochemist Ariel Anbar of Arizona State University, calls the retraction explanation 'unbelievably misleading,' saying the evidence for contamination in the original study was weak and should be adjudicated by scientists, not the journal. 'You would think that if Science wanted to retract this paper after nearly 15 years, they would be able to come up with a clear, convincing argument for the published record—developed transparently and presented coherently. You would be wrong.'
A NASA official has also asked Science to reconsider the retraction, saying the journal has 'singled out' the study and that the decision upends scientific standards.
In some respects, the arsenic life saga is less about the disputed result itself and more about the zeitgeist in which it emerged. The study debuted at a seminal moment when the stately and slow tradition of scientific peer review was speeding up and moving online, opening up to the wider scientific community and closely coupling with the 24/7 churn of social media and digital news. With the benefit of hindsight, the ensuing furor was if nothing else a warning about 'big, if true' research results rapidly rolled out to breathless fanfare—in this case the now notorious NASA news conference. Wolfe-Simon, then a 33-year-old NASA astrobiology fellow, became a scientific celebrity practically overnight—and also a lightning rod for controversy.
The research team's decision to engage minimally with online criticism while handling disagreements in the more formal, slow-moving world of scientific journals played badly in the burgeoning blogosphere era, with effects that linger clearly today. 'Over the years, Science has continued to receive media inquiries about the Wolfe-Simon Research Article, highlighting the extent to which the paper is still part of scientific discussions,' Thorp noted in the retraction statement.
In February questions of retracting the study were apparently revived by a New York Times profile of Wolfe-Simon that portrayed her and the search for arsenic life in sympathetic terms. Amid the profile's publication, Anbar says, he and other study authors received queries about a retraction from the journal, followed by a notification of its decision to proceed with a plan to retract (against the authors' stated disagreement). The authors eventually okayed a draft of the retraction that made it clear that there was no misconduct, but the stated basis for retraction was still vague, Anbar says.
'My conclusion is that, yes, the paper should be retracted so that a statement of caution appears whenever it is accessed,' says Patricia Foster, an emerita professor of biology and research ethicist at Indiana University, noting that it was still generating fresh citations in peer-reviewed science papers. But, she adds, it's important that the retraction notice makes clear that no research misconduct is suspected about the work.
Leonid Kruglyak of the David Geffen School of Medicine at the University of California, Los Angeles, a co-author of one of the 2012 papers that found that GFAJ-1 merely sequestered arsenic, also agrees with Science 's retraction. It is now appropriate based on the new standards for retracting papers with seriously flawed conclusions such as the GFAJ-1 study, he says. 'I don't think this is really a dispute, except on the part of the authors themselves.'
One critic of the retraction, however, is chemist Steven Benner of the Foundation for Applied Molecular Evolution, who sat on the 2010 NASA news conference as a skeptical voice. Science, he says, shouldn't act as a 'gatekeeper' by retracting a study that might be wrong but wasn't fraudulent; doing so carries its own threat to open scientific research, in his view. 'The paper should stay, and it has simply met the fate of many papers that were wrong,' he says. 'It's an object lesson on how wonky results get fixed.'
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