December 03, 2010

My summary of NASA's arsenic-thriving bacteria story

Almost instantly after coming home from work yesterday, I noticed a steady stream of mentions of a mysterious and hugely hyped NASA press conference scheduled for later in the day trickling in via Facebook, Twitter, blogs and news sites. I got excited, but also a bit confused. NASA's announcement seemed spectacular enough:

NASA will hold a news conference at 11 a.m. PST on Thursday, Dec. 2, to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life.

After much speculation, what we all now know was revealed at the press conference:

Researchers conducting tests in the harsh environment of Mono Lake in California have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism substitutes arsenic for phosphorus in its cell components.


Source: xkcd. "According to a new paper published in the journal Science, reporters are unable to thrive in an arsenic-rich environment."

A discovery that according to NASA means that "the fundamental knowledge about what comprises all known life on Earth" has changed and that "the definition of life has just expanded". Hyperbolic much? The paper that describes these new findings was published in advance yesterday in Science, find the link at the bottom of the post, and there are indications that associated papers with more details will be published in the coming months.

It's been exciting to follow the reporting pretty much directly as it's happened and I've been Tweeting and Facebooking the story unfolding almost in real time since yesterday. All in all this story has been a great exercise in observing how online science reporting works and how blogs and social media works within this context.

By this time yesterday the furore was on:

Phil Plait's Bad Astronomy blog was very early in giving a measured but enthusiastic summary; "NASA's real news: bacterium on Earth that lives off arsenic!", so enthusiastic that a few errors, now corrected, made their way in. For the best and most sensible summary and background I would point to Carl Zimmer's excellent post "Of Arsenic and Aliens", which was posted simultaneously with NASA's press conference. Soon enough SciTech news sites started picking up the story: WIRED titled its report "NASA Finds New Arsenic-Based Life Form in California". New Scientist sank to new and lower lows with the headline "Arsenic-based bacteria point to new life forms", although they do a good job at presenting the doubts that remain about the finding. The Guardian's science pages started tracking the story pretty soon as well, posting links to the different reports as they were coming in: "Nasa unveils new life form: Bacteria that thrive on arsenic".

The somewhat fallacious tendency to call this a "new life form" becomes really apparent at this point, no doubt fueled by the sensationalistic NASA press conference and its astrobiology angle. Many reports give the impression that the arsenic-thriving bacteria represent some sort of "alternative" branch of life, or a primordially ancient form of life that we weren't aware of, which is incorrect, or that the bacteria were discovered incorporating arsenic into their cellular mechanisms in their natural environment, which is also incorrect.

Here in Sweden the major newspapers also ran spectacular headlines about the "new life form": Dagens Nyheter wrote "New life form discovered in a lake of arsenic", and Svenska Dagbladet followed with the not quite as wrong "The bacteria that lives on arsenic".

An interesting aspect in the stream of information is how the story itself has evolved since the first reports and the press conference. At first it wasn't clear from many reports if they had actually proven that the arsenic-thriving bacteria incorporated arsenic instead of phosphorus into their DNA, and what exactly the evidence was. Some reports presented doubts about the evidence, some didn't, but several have had to append or correct their information. Many still remain tentative about whether or not the evidence is sufficient to claim that arsenic was incorporated into the bacteria's DNA, not to speak of other cellular components that include phosphorus such as the cell membranes and ATP. This is all "science as usual", but the "science-report-by-press-conference" strategy doesn't exacly mirror the long and tentative process of scrutiny that all scientific findings have to go through even after publication.

I think that perhaps our demands for a clear and instant message are too high?

Aside from Carl Zimmer's post, I can recommend the following science blogger's takes on the story: Greg Laden's "NASA's new organism, the meaning of life, and Darwin's Second Theory", which focuses on the evolutionary implications, and PZ Myers' "It's not an arsenic-based life form", which very clearly describes the actual experiments and findings. Ed Yong's "Mono Lake bacteria build their DNA using arsenic (and no, this isn’t about aliens)" also adds some background to the field of study of arsenic-loving microorganisms and warns against going overboard with the conclusions.

Notice how RealScientists(TM) avoid writing about "new life forms".

In the end though, there's no doubt this is an exciting and significant finding, and the reason this will become THE scientific story of 2010, at least attention-wise, is not just because of the shrewd media strategy. Yet I can't help but being a bit cynical about the whole THIS WILL CHANGE EVERYTHING 4-EVER!!!!1 hype, especially since it very easily can lead to widespread misconceptions about biology.

Wolfe-Simon, F., Switzer Blum, J., Kulp, T.R., Gordon, G.W., Hoeft, S.E., Pett-Ridge, J., Stolz, J.F., Webb, S.M., Weber, P.K., Davies, P.C.W., Anbar, A.D., Oremland, R.S. (2010). A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus Science : 10.1126/science.1197258

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