Public peer review

by Jennifer Eve Appleton

The world of science blogging was taken over with an almost instantaneous critiquing frenzy with the publication of a paper claiming the finding of extraterrestrial life. Four days before the publication of an online paper in Science magazine, NASA sent out a media advisory that it was going to hold a press briefing to discuss an extraordinary finding in the search for extra terrestrial life. This led to wild speculations on the web, even more so when the paper was published in Science on 2 December 2010. The media headlines to follow were of an ‘alien nature’.

Californian scientist Fellisa Wolfe- Simon, who had a NASA fellowship in astrobiology, published a paper about the discovery of bacteria which used the usually poisonous element of arsenic and other molecules instead of phosphorous in its DNA. These bacteria were found in Lake Mono, a lake full of arsenic rich water in a volcanic valley southeast of Yosemite national park. They suggested it as an alternative scheme to life as we know it; later growing the bacteria in the laboratory on a diet of arsenic they were surprised to find that the microbes eventually fully incorporated it into their cells. A chemical analysis with radioactive tracers showed that the GFAJ-1 strain bacteria were in fact using arsenic in its metabolism.

NASA staff found that some bacteria (GFAJ-1) thrived when they had access to phosphorus followed by exposure to a highly toxic culture rich in arsenate. Their results suggested that the bacteria replaced the element vital for life – phosphorus – with arsenic, which has similar chemical properties. They suggested the bacteria were replacing the phosphorus with arsenic in their DNA. If correct, it meant that they had found a new form of life on Earth, which also showed the essential requirements for life to live elsewhere.
Media hype soon followed, with the Daily Mail brandishing headlines such as ‘Alien life may have been discovered on earth lurking deep in Californian lake’. A corresponding picture of ET was duly attached.

of an alien nature..

When the paper was published it was criticised immediately in a blog by Professor Rosie Redfield who runs a microbiology research lab in British Columbia. She argued: “There was phosphorus in the culture and the authors did not calculate whether the amount of growth they saw in the arsenate only medium could be supported by the amount of phosphate present.”

Critics such as Ed Yong- who writes the popular blog Not Exactly Rocket Science- also blogged that the paper showed there was a small amount of phosphorus in the testing medium used, and also that the bacteria originally lived in Lake Mono. The lake itself contains a particularly high concentration of phosphorus than anywhere else on Earth, therefore there would be no selective pressure for a life based on arsenic to evolve.

The scientist Fellisa Wolfe-Simon and her colleagues came under attack by journalists when they declined to respond to media calls for clarifying answers to questions. They were shocked by the reaction to the press conference arranged by NASA and at the overall response to the papers publication, thinking that their findings would interest the general public and simply generate a discussion for further research amongst their peers. The hype was huge, demonstrating that whatever the Internet gives voice to spirals onwards and upwards.

The researchers needed to continue consolidating work and to produce supplemental online material and data for others to use. The attention gained due to the media and the ensuing criticisms from fellow scientists offered them access to expensive tools which would easily test whether or not the DNA contained arsenic in place of phosphorous. Such equipment the NASA scientists claimed they did not have the budget to provide; the authors further admitted they wanted the results published quickly.

However, in defense of NASA they did not say in their publication – as the media reported – they had found bacteria that naturally used arsenic to live; instead, they clearly stated that although the bacteria were naturally occurring in a high arsenic environment they used phosphorous to live.

Although generating a good story and encouraging debate in the form of a public peer review, the paper did not show proof of extra terrestrial life. Nevertheless, as Simon Conway Morris of Cambridge University said, “It did show the underappreciated versatility of life.” This in itself must warrant further examination…

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