Last week, NASA made a big hullabaloo about a microbe that they had “trained” to consume arsenic instead of the normal phosphorus. The discovery was said to open up all sorts of new possibilities when it came to what sorts of environments we could theoretically discover life in on other planets.
A week later, it looks like the paper is fatally flawed.
But how could the bacteria be using phosphate when they weren't getting any in the lab? That was the point of the experiment, after all. It turns out the NASA scientists were feeding the bacteria salts which they freely admit were contaminated with a tiny amount of phosphate. It's possible, the critics argue, that the bacteria eked out a living on that scarce supply. As Bradley notes, the Sargasso Sea supports plenty of microbes while containing 300 times less phosphate than was present in the lab cultures.
"Low levels of phosphate in growth media, naive investigators and bad reviewers are the stories here," said Norman Pace of the University of Colorado, a pioneer of identifying exotic microbes by analyzing their DNA, who was another co-author on the weird-life report.
That’s a pretty fatal flaw. Unfortunately, this is the sort of thing that happens when millions of dollars in government grants are out there to be won and fame to be had.
Skepticism is good for science.